In 1775, the Continental Congress enacted the Articles of Conduct, governing the ships and men of the Continental Navy. However, all of these ships were soon sold and the Navy and Marine Corps were disbanded. In July 1797, Congress authorized the construction of six ships and enacted the Rules for Regulation of the Navy as a temporary measure. Then, in 1800 Congress enacted a more sophisticated code adopted directly from the British Naval Code of 1749. There was little or no need for lawyers to interpret these simple codes, nor was there a need for lawyers in the uncomplicated administration of the Navy prior to the Civil War.

During the Civil War, Secretary of the Navy Gideon Welles directed a young D.C. Assistant U.S. Attorney, Nathaniel Wilson, to present the Government’s case in complicated court-martial. Without any statutory authority, Secretary Welles named Wilson the “Solicitor of the Navy Department,” making him the first House Counsel to the U.S. Navy. By the Act of March 2, 1865, Congress authorized the President, “To appoint, by and with the advice and consent of the Senate, for service during the rebellion and one year thereafter, an officer of the Navy Department to be called the ‘Solicitor and Naval Judge Advocate General.’” Congress maintained the billet on a year-to-year basis by amendments to the Naval Appropriations Acts. In 1870, Congress transferred the billet to a newly established Justice Department with the title of Naval Solicitor.

Colonel William Butler Remey, U.S. Marine Corps, became the first uniformed chief legal officer of the Navy in 1878. Colonel Remey was able to convince Congress that the Navy Department needed a permanent uniformed Judge Advocate General and that, because naval law is so unique, it would be better to appoint a line officer of the Navy or Marine Corps. The bill to create the billet of Judge Advocate General of the Navy was signed in 1880.

The Naval Appropriations Act of 1918 elevated the billets of Navy Bureau Chiefs and Judge Advocate General to Rear Admiral. In July 1918, Captain George Ramsey Clark was appointed the first Judge Advocate General to hold the rank of Rear Admiral. In 1946, the Naval Justice School was established at Port Hueneme, California, to provide legal training for all Navy, Marine Corps, and Coast Guard lawyers, enlisted legal professionals, active and reserve.

In 1947, the Navy created a “law specialist” program to allow line officers restricted duty to perform legal services. By the Act of May 5, 1950, Congress required that the Judge Advocate General be a lawyer. The Act also required each Judge Advocate General of any service be a member of the bar with not less than eight years of legal duties as a commissioned officer. The Act also enacted the first Uniform Code of Military Justice. By 1967, the Navy had 20 years of experience with the law specialist program. There was, however, increasing pressure to create a separate corps of lawyers. That year, Congress established the Judge Advocate General’s Corps within the Department of the Navy. The legislation was signed into law by President Lyndon B. Johnson on December 8, 1967, and ensured Navy lawyers’ status as members of a distinct professional group, similar to physicians and chaplains.

On January 4, 1972, Secretary of the Navy John H. Chafee approved the recommendation for the establishment of the Legalman rating. A memorandum from the Chairman of the Rating Review Board announced the approval, stating in part, “…the scope of the new rating will provide judge advocates with the personnel trained in court reporting, claims matters, investigations, legal administration, and legal research. This scope is in consonance with the new concept in the civilian legal community where many areas of legal services can be provided by competent trained personnel under the supervision of a lawyer…” On October 4, 1972, 275 petty officers were selected for conversion to the new Legalman rating.

On December 3, 1973, by Notice 5450, the CNO officially established the Naval Legal Service, “to administer the legal services program and provide command direction for all Naval Legal Service activities and resources as may be assigned; and to perform such other functions or tasks as may be related to the Naval Legal Service as directed by the CNO.” Navy Legal Service Offices (NLSO), were created in 1976 and responsible for providing defense and legal assistance to eligible personnel; Trial Service Offices (TSO), which were established in the mid-1990s and responsible for providing courts-martial prosecution, court reporting and administrative trial support; and Staff Judge Advocates (SJA) providing legal advice to U.S. naval base commanding officers. In 2005, the Judge Advocate General of the Navy approved the merger of the Navy's Trial Service Offices and Staff Judge Advocates into new commands known as Region Legal Service Offices (RLSO).

In 2007, the Legalman education and training pipeline was adapted in order to fully train Legalmen as paralegals. The Naval Justice School’s (NJS’s) curriculum was adapted to include four American Bar Association- (ABA-) approved paralegal college courses. Legalmen now leave NJS with 10 semester hours of college in paralegal studies.

On October 1, 2012, the eight NLSOs were disestablished and four Defense Service Offices (DSO) were established. The legal assistance mission that was previously performed by NLSOs was transferred to the RLSOs. The DSOs focus solely on defense services and personal representation advice for servicemembers.

Today, the Judge Advocate General directs a worldwide organization of active and reserve component judge advocates, active and reserve component enlisted, and civilian personnel. The JAG provides legal and policy advice to the Secretary of the Navy in all legal matters concerning military justice, administrative law, environmental law, ethics, claims, admiralty, operational and international law, litigation, and legal assistance.