Starting a Military Career: Understanding the Different Branches of the United States Military

What Does Each Branch do, and What do They Have to Offer?

Different Branches of the MilitaryThe United States military has a rich history that dates back centuries. Ever since the country began, the need to protect civilians and the nation’s interests as a whole have been a priority. Over time, the military turned into six separate branches, with each one having its own active-duty and reserve members. These people go through an intense training to ensure that they can meet the physical, mental, and emotional requirements for anyone who wants to protect America.

These six branches include the Army, Navy, Marines, Coast Guard, Air Force, and the newest addition, Space Force. Together, they investigate threats against Americans and their allies, defending against them on land, in or underwater, and in the air. Although they have common goals, these branches are very different organizations with unique rules, requirements, and functions. This means that someone who wants to enlist in the U.S. military should carefully consider which branch is the most appropriate for them. It depends on the career that people plan to have with the service, as well as how long they plan to stay in it. With this information, people will understand the primary distinctions between each branch as well as their general opportunities and why someone might join them.

History of the United States Military Branches

People tend to think of the United States as not starting until 1776 at the very earliest, but the military was one step ahead. As a way to protect the colonies’ interests against the British right before the War for Independence, rebel leaders started the U.S. Continental Army in June 1775. The Continental Navy began in October 1775, followed shortly thereafter by the Continental Marines in November. The Coast Guard came along in 1790, after the United States had officially become its own nation. The need for these services rose because of Britain’s world-class, large Navy. Given that most of the early colonies relied on coastal seaports for survival, much less trade, the ability to defend against the British was paramount.

The latest branches of the U.S. Armed Service relate specifically to the air. The Air Force actually began in 1907, shortly after the invention of aircraft. It became its own division in 1947, separate from the Army. The last is the U.S. Space Force, an air-based service focused on the protection of U.S. interests from above. It was created in 2019.


As the country’s oldest branch of the military, the United States Army serves as a ground force providing protection for U.S. interests and stability here and abroad. At present, the army maintains a roster of nearly 500,000 soldiers and officers. Some may serve part-time in the Army reserve or the Army National Guard. The rest are in full-time positions, which last from two years up to a whole career. Some people enlist and work their way up, while others participate in programs that allow them to become officers after they finish.

The army is organized by groups of soldiers headed by an officer appropriate to the responsibility. These units have names like:

  • Squad
  • Platoon
  • Company
  • Battalion
  • Brigade
  • Division
  • Corps

Each unit does not necessarily have a specific number of members; it depends mostly on the job they are required to do. Officers in the higher ranks, like colonel or general, command units representing thousands of people. In these larger units, enlisted soldiers may still operate under the direction of the officers in charge of their company. But since the army is highly hierarchical, the directions given are typically handed down from a higher official.

Army Reserve

The Army Reserve is a part-time program that people can participate in without having to commit full-time to being a soldier. As a reservist, someone receives the same basic training that all army enlisted soldiers receive. In exchange, they are designed to be ready to mobilize in the event they are needed. Otherwise, they commit to one weekend a month and two weeks of full-time work per year. This helps them to retain their skills and participate in limited army programs related to their term of service. Many full-time soldiers in the army become reservists to complete their term.

Army National Guard

Like the Army Reserve, the Army National Guard is meant to be part-time for those who enlist in it. Unlike other reservists, who may be called to serve wherever the U.S. has an army station, members of the Army National Guard remain on domestic soil to serve U.S. interests at home. They also receive the same training and preparation as anyone who enlists in the army. In exchange, they are ready to report to the governor of their state during times of emergency. Otherwise, they may choose to work or attend school within their state.

Army Basic Training

As a general rule, Army Basic Training is 10 weeks of grueling exercise, practice, and study. The length of the training depends on the person’s military occupational specialty (MOS). Some specialties require training that lasts weeks longer, or requires participants to remain in the same unit for their basic training and their advanced training. People will be called to one of four possible locations in Georgia, Missouri, Oklahoma, or South Carolina.

People can expect the training to last many hours a day—much longer than a standard workday. During this time, they will:

  • Study common army terms and designations
  • Learn army history and traditions
  • Exercise and improve their physical strength and stamina
  • Practice skills related to their MOS
  • Prove on multiple occasions that they can meet the physical and mental standards required for a soldier

The course is often divided into periods lasting a few weeks at a time. Each one focuses on different aspects of people’s individual roles as enlisted soldiers.

Because basic training can be an arduous process, there are things that people may want to do in advance to prepare. The first is to improve their physical condition and ability to sustain physical work for hours at a time. They may also choose to research common aspects of the army, like the ranks, values, or phonetic alphabet. Once the training is complete, most people move to Advanced Individual Training, where they develop skills related to their particular MOS. It may be at the same location or a different one.


Ultimately, most people who choose to enlist in the Army do so because they want to be part of a ground force protecting the U.S. or its interests abroad. Although traditionally the Army moved in large units, the needs of the 21st century dictate a smaller, more targeted force. People who enlist in the Army need to be prepared to move on land, no matter what type of land it is. In exchange, they may get the opportunity to spend a lot of time outdoors and travel extensively around the world.

Air Force

United States Air Force

The United States Air Force got its start in 1947. This highly competitive branch of the U.S. military maintains a force of over 300,000 members. It is the most recent independent branch to be created, but also one of the most versatile. People in the Air Force may serve in a variety of capacities or organizations such as the maintaining of air superiority, global mobility or attack, information management, or combat support. People in the Air Force can be deployed virtually anywhere in the world and often do so much more rapidly than other branches.

In order to qualify for the Air Force, interested applicants must complete a test called the Armed Services Vocational Aptitude Battery. The purpose of this test is to determine what a person’s aptitude could be for certain types of jobs within the military. In order to qualify for the most coveted roles of the Air Force, people generally must score very high on the test. In exchange for this qualification, people may be able to secure jobs that are similar to civilian work, with less emphasis on direct combat. This, along with a higher rate of pay, is partly why this branch is so competitive.

Air Force Reserve

The Air Force Reserve makes up almost 20% of the total Air Force. Members of the Air Force Reserve may choose to take this role with no military experience, or as a way of continuing their service on a part-time basis. People who enlist in the Air Force Reserve receive similar training. They may also choose to take on similar jobs, depending on their ASVAB scores and what is available at the time. They receive full-time benefits for part-time work, with the presumption that they could be called on at any time.

Air National Guard

Similar to the Army National Guard, members of the Air National Guard complete basic training and then serve part-time with one of 140 units throughout the U.S. The requirements to join are similar to the Air Force in general. People must take the ASVAB test and be between the ages of 18 and 38. Unlike the Army National Guard, the Air National Guard can be called upon by both state and federal governments. Typically, Air National Guard units remain in their home states for work, but they may be called elsewhere.

Air Force Basic Training

As with other branches, Air Force Basic Training is a full-time effort to develop a higher physical condition while learning the standards of the Air Force and the tasks important to any role in this part of the military. People often find that this period, which lasts about nine weeks, provides them with a lot of information and opportunities to practice. This training is shorter than other branches, which means as much as possible is packed in from the beginning.

Initially, participants start to refine their physical abilities. They also complete the basic procedures necessary to be a part of the Air Force, like medical appointments and vaccinations. As the weeks progress, they learn more about the branch’s standard operating procedures. Once they have started to build their endurance, they learn how to operate weapons and get ready for combat. By the end, they are ready to take their final tests and get ready to relocate.

People find it helpful if they spend some time preparing for the work they will do in basic training before they get an official date. Many prospective soldiers focus on physical activities such as their ability to run a mile in less than ten minutes or perform a higher number of push-ups or sit-ups. It is also important for them to consider the mental and psychological aspects. People may want to read the Uniform Code of Military Justice, reporting and saluting procedures, and work on retaining information over time.


Given its area of focus, the Air Force is widely regarded as an excellent way to prepare for a civilian career after a person’s term of service. Access to technology and paid training can set someone up well for high-paying jobs in information or consulting. As a member of the Air Force, people may participate in combat, but it tends to be much more indirect. In some cases, it may even be remote, operating equipment from miles away.

The United States Navy originated in 1775, with a goal to protect American interests on water and near sea ports. The U.S. Navy has nearly 350,000 active-duty members, with another 100,000 or so in the reserve. People who join the Navy and complete a course of training may be stationed in one of almost 300 ships, or in a nearby port. While many members of the Navy participate in active warfare when appropriate, others work in support roles on ships or on U.S. territory. Elite teams include the Navy SEALs and Navy Divers, which require specialized training and placement within a highly competitive unit.

When people join the Navy, they are usually required to commit to a term of at least four years. Some commitments call for a shorter term. This usually involves a short period of intense training, followed by placement in a program of more than 80 specialties. Navy sailors may be stationed almost anywhere in the world, depending on their positions. Some of these positions may include work on an aircraft carrier, which is not unlike a small, floating city. The result is a specialized force that is ready to mobilize quickly.

Navy Reserve

Like other branches of the military, the Navy has a reserve force ready to move into a full-time role when needed. People may choose to enlist in the Navy Reserve if they are between the ages of 18 and 35, after they pass the ASVAB test and prove that they can handle the physical requirements. Many current members of the military decide to become a reservist after years of active duty, because this allows them to work part-time but receive the same training and many of the same benefits and opportunities that active-duty members get.

Navy Boot Camp

Navy Boot Camp is about eight weeks of endurance building and training for a career in the Navy. During this time, people are generally pushed to the limits of their strength and energy. Training is completed on Lake Michigan and includes a variety of tests and experiences designed to mimic what people can expect from warfare or necessary work on a ship.

At the beginning, everyone reporting to boot camp must complete the Initial Navy Fitness Assessment. This requires them to run a mile and a half within a certain amount of time, with differing numbers for men and women. If they do not pass, they must retake it within two days and pass it. People may choose to start practicing similar exercises before they arrive. As a general rule, it is easier to build endurance when recruits already have a reasonable degree of physical fitness. Those who pass the initial assessment can move on to learning more complicated physical maneuvers, which include several battle stations to cover various aspects related to Navy life.

While recruits are expanding their physical skills, they are also learning about Navy commands, rules, and traditions. These can be arduous to learn, so people should expect to invest many hours studying and memorizing. There are points where people must be able to recite information by rote. At the conclusion of the training, those who meet the standard of excellence will graduate and be told where to report.


Joining the U.S. Navy often comes with enlistment bonuses and the possibility at a high-powered, prestigious career. Although there are 80 specialties and subspecialties, some are more competitive and harder to access than others. As a general rule, people will determine what they are eligible to apply for based on their ASVAB score. Popular programs include:

  • Naval Air
  • Naval Nuclear Power
  • Navy Special Operations

Only a small number of people will qualify for these kinds of jobs. However, people can study different kinds of technology or relevant fields like medicine for various Navy positions, which will give them greater opportunities when their terms is complete.

Marine Corps

United States Marine Corps

Members of the United States Marine Corps are somewhat different than members of the U.S. Army or U.S. Navy. Specifically, Marines are trained in combat both on land and at sea. This means that, similar to the Army, they focus primarily on warfare. The main distinction is that they are versatile, trained to fight in a variety of conditions. This has been a chief aim of the Marines since the first battalions in 1775, although this branch was not officially separated until decades later. At less than 200,000 active-duty members, the Marines represent a much smaller group than the Army, Navy, or Air Force.

The service commitment for Marines is at least four to six years, which is longer than some other branches. Eligible applicants are typically younger as well. People who want to enlist must be 18 to 29 years old and have a high school diploma. Each recruit has to go through 12 weeks of training in South Carolina or California. Once approved, they can be stationed anywhere throughout the world. To become an officer, Marines typically need to enlist after completing a college ROTC program or complete it during their term of service.

Marine Corps Reserve

The Marine Corps Reserve is a reserve branch of less than 100,000 people. Many of these members are former Marines. They appreciate the ability to continue to receive benefits and a part-time income while they develop a civilian career or go to college. Although this is the typical route, some people decide to enlist straight into the Reserve. Regardless, they receive the same 12 weeks of training, and like other branches, reservists devote two weeks a year and one weekend a month to maintain their skills.

Marine Corps Boot Camp

The location for Marine Corps Boot Camp depends on a recruit’s location and gender. Anyone who lives east of the Mississippi, as well as any women, go to Parris Island in South Carolina. Men who live west of the Mississippi go to San Diego, California. Boot Camp is designed to determine whether or not a recruit can handle the physical stresses of warfare on land or water while expanding their skills and strength for their term in the Marines.

Like the Army, Marine Corps Boot Camp runs in a series of phases. Each one focuses on a different kind of challenge that recruits need to pass in order to graduate. Like other branches, the Marines requires people to pass an initial test of physical condition. Many recruits find it helpful to spend a few weeks or even a few months gradually building up to the test.

The first phase focuses on endurance and the study of Marine history and customs. The second phase teaches marksmanship, where recruits spend a lot of time on the field developing these skills. The third phase works on survivor skills during warfare, which is widely considered one of the hardest phases to pass. The fourth phase shows recruits what it means to be a Marine for years. The final step is called the Crucible, a two-day event where recruits can demonstrate all they have learned and prove that they are ready to graduate. Once complete, graduates get a brief leave before they must report for duty.


The Marine Corps is an ideal choice for people who want to have a comprehensive experience focused on battle. Marines spend a great deal of time learning the best ways to fight war, meaning that people who are looking for an opportunity to fight would be well-suited. Marines are some of the quickest to deploy because they can function in both landed infantry and amphibious assault. On the other hand, people who are looking for a military branch as a way to get to a civilian career should choose a different branch. The Marines specialize in many fields, but people who want to go into something like a medical field would need to get preparation elsewhere.

Coast Guard

Although the United States Coast Guard is considered a branch of the U.S. military, its operations can be significantly different. The Coast Guard is designed to provide:

  • Security
  • Defense
  • Search and rescue
  • Law enforcement

The Coast Guard operates under the U.S. Department of Homeland Security, which distinguishes it from other branches that operate under the Department of Defense. In times of war, its management can be shifted to the Secretary of the Navy. However, this has only happened twice. The first came in 1917 related to World War I. The second came in 1941 related to World War II.

The Coast Guard can be an excellent career choice for people who want to remain in the U.S. but serve their country. Because this branch emphasizes less work in warfare and more local enforcement, many people consider it good preparation for similar careers in police or security organizations. With fewer than 50,000 active-duty members, it is one of the smallest branches. People who serve in the Coast Guard must be very good swimmers, a skill they have to maintain regularly. The members who perform search and rescue enjoy one of the most elite positions available in the military.

Coast Guard Reserve

The Coast Guard Reserve has some of the most flexible age requirements for people who can meet the service’s strict training and fitness obligations. Adults up to age 39 are encouraged to apply, especially if they have already served in active-duty for the Coast Guard. As with other military branches, the Coast Guard provides the same training for recruits and reservists. Once the training is complete, reservists are allowed flexible options for working and living, as long as they retain their skills with regular sessions at least once a month.

Coast Guard Boot Camp

Coast Guard Boot Camp lasts about eight weeks and is located in New Jersey. Each week focuses on refining physical skills, as well as learning rescue techniques and other aspects of coastal seamanship. During the training process, recruits must pass a midterm exam and multiple fitness tests throughout. The fitness requirements are stricter than they are for many military recruits, because people are relying more on their physical strength than the use of weapons or tools.

One of the biggest distinctions between Coast Guard Boot Camp and other forms of military basic training is the focus on swimming. For most other branches, recruits should be able to run a significant distance in a short period of time, plus perform other body weight exercises as a way to pass their initial test. Recruits of the Coast Guard must demonstrate their ability to swim well and long distances by the beginning of the second week. As such, those who are interested in training for the Coast Guard may want to prepare by exercising and developing their swimming skills, particularly as it relates to assisting others in the water.

The last half of Coast Guard Boot Camp emphasizes skills needed to enforce U.S. law while on the water, which includes firearms training. The last few weeks include testing of all skills built throughout training in a series of mock battles and exams. The recruits who have met all the requirements graduate and are given their assignments.


The U.S. Coast Guard is an excellent career choice for people who are looking toward a future in law enforcement. The strict requirements for entry and continuation in the service help prepare people for the requirements they will need to maintain for other jobs that emphasize physical strength. It is also ideal for people who want to spend a lot of time in the water. However, as it is such a selective branch, prospective recruits should ensure that they are in the best position to apply.

Space Force

The latest addition to the U.S. military is the United States Space Force. This branch was started in December 2019 under the National Defense Authorization Act for 2020. Although Space Force is considered a separate branch of the military, it operates under the direction of the Secretary of the Air Force. The goal of the Space Force is to protect American interests in space. Specifically, it concerns protection of the U.S. from space and while in space. With only about 2,500 active-duty members, it is the smallest branch of the armed services.

Although the primary aim of the Space Force is to protect Americans against competing interests on Earth, there are other goals for the service. These include:

  • Researching and investigating space mobility
  • Analyzing the ability to transmit information through space
  • Developing resources for protection of the U.S. and allied countries
  • Increasing capacity for defense
  • Improving survivability in space

Because the service is so new, its funding is only guaranteed for the first 18 months. Afterward, Congress must authorize money to continue its development and expansion.


Although the Space Force is a new and exciting frontier for the U.S. military, people who want to enlist must take more traditional routes. As a general rule, they must enlist through the U.S. Air Force and complete its basic training. Given the high degree of training required for air travel beyond Earth’s atmosphere, only the most elite candidates are eligible for placement in this program. People who meet the criteria may apply for one of 16 specialties, half of which are designated for Air Force officers. Opportunities may expand over time.

Choosing a Military Branch to Join

The U.S. military may seem like one huge organization, but it is made up of several pieces. These pieces represent millions of people who serve as active-duty members, reservists, officers, and leaders. Each branch provides a layer of protection for American civilians, residents, and allies inside the country and abroad. The Army represents the land, while the Navy and Coast Guard attend to the water. The Marines act as a bridge, protecting U.S. interests on land and water interchangeably. The Air Force and new Space Force consider America’s needs and vulnerabilities from the air.

Most people spend at least a few years serving once they pass training, as this is a requirement for virtually any branch. During this time, they receive experience that they may use for a valuable civilian life after their terms are complete.