A native of San Diego, California, James E. McPherson graduated from San Diego State University in 1977 with a bachelor’s degree in public administration. He received a Juris Doctor in 1981 from the University of San Diego School of Law, and in 1991 he was awarded a Master of Laws in Military Law from The Judge Advocate General’s Legal Center and School in Charlottesville, Virginia.

McPherson first gained military experience as an enlisted member of the U.S. Army, serving as a military policeman at the Presidio of San Francisco, the Eighth Army in South Korea, and the First Infantry Division. In 1979, McPherson was commissioned as an ensign in the United States Navy Judge Advocate General's Corps. In October 2002, McPherson was promoted to the grade of Rear Admiral upper half and assigned as the deputy judge advocate general for the Navy and Commander, Naval Legal Service Command. On Nov. 10, 2004, McPherson assumed duties as the 39th judge advocate general of the Navy, his final assignment.

After leaving active duty, he served as general counsel for the Department of Defense Counterintelligence Field Activity followed by service as the executive director of the National Association of Attorneys General, a professional association of the state, territorial, and District of Columbia attorneys general.

McPherson was selected as the 22^nd General Counsel of the Army in January 2018, during which time he provided legal counsel to the Secretary of the Army and senior members of the Army Secretariat.

In March 2020, he was sworn in as the 34^th Under Secretary of the Army, serving as the Secretary of the Army’s senior civilian assistant and principal adviser on matters related to the management and operation of the Army. 

On April 8, 2020, McPherson was appointed Acting Secretary of the Navy.

His military decorations include the Distinguished Service Medal, the Legion of Merit (two awards), the Meritorious Service Medal (four awards), the Army Commendation Medal, and the Navy Achievement Medal (two awards).