Service members with paygrades E-1 through E-3 are often either on their first assignment or in some sort of training status. The training includes the fundamental training stage, during which recruits are exposed to military culture and ideals and are taught the fundamental skills needed for their service component. A phase of specialized or advanced training that gives recruits a particular area of competence or concentration comes after basic training. This field is recognized as a rate in the Navy. The midlevel enlisted ranks (E-5 to E-7) see a major increase in leadership responsibility. The designations noncommissioned officer and petty officer are used to formally recognize this duty. Senior advisers to commanders on enlisted matters, E-8s and E-9s have 15 to 30 years of experience in their positions.

Warrant officers are experts in specific military technology or capabilities and possess warrants from their service secretaries. When promoted to chief warrant officer 2, the lowest-ranking warrant officers, who work under a warrant, start receiving commissions from the president. These commissioned warrant officers serve as the president of the United States' personal emissaries. In contrast to commissioned officers, who are generalists, they obtain their authority from the same source as commissioned officers yet continue to be experts.

Members of the Navy or Navy Reserve who have completed Officer Training and have a degree from a four-year college or university are known as commissioned officers. NROTC, the Naval Academy, and other undergraduate degree options are four-year college commissioning programs. On the basis of substantial service experience, there are, however, waivers to the degree requirement. Officer duties can be found at all levels of command, from low-level management to middle management.

The United States Navy's four-star commissioned officer rank of admiral, sometimes known as a flag officer, is abbreviated as ADM. The admiral grade is the highest position an officer can hold in the United States Navy because the five-star fleet admiral grade has not been in use since 1946. The number of four-star admirals that may be called to active service at one time is restricted by U.S. law. For the Navy, a maximum of 160 flag officers may be on active service. The maximum number of four-star officers that may be assigned to each service is regulated by statute at a maximum of around 25% of the flag officers in each service. This is set at six Navy admirals with four stars. To accommodate practical requirements, exceptions are allowed to this restriction. Nine four-star admirals were on active service with the U.S. Navy as of July 2020.