Brigadier General Composto retired from active duty on January 1, 2004, following his assignment as the Commanding General, Marine Corps Base, Quantico, VA.

Brigadier General Composto was commissioned via the Marine Corps PLC program at St. John's University, New York, NY, in June 1971. Receiving his B.A. degree in history, Brigadier General Composto also earned a J.D. degree from St. John's University Law School (1974); and a M.A. degree in National Security and Strategic Studies from the Naval War College, Newport, RI (1991). After graduating with honors from both The Basic School, Quantico, VA, and the Naval Justice School, Newport, RI, he was designated a Marine Corps Judge Advocate in October 1975.

Following The Basic School, he served with the 3d Marine Aircraft Wing, MCAS, El Toro, CA as a trial counsel, defense counsel, review officer and chief review officer from May 1975 to April 1978. Brigadier General Composto transferred to Okinawa, Japan, where he served as a review officer, trial counsel, and Head, International and Administrative Law Branch.

Upon returning from Okinawa, he attended Amphibious Warfare School, Quantico, VA, from August 1979 to May 1980. After graduating, he remained at Quantico where he served in the SJA's Office until July 1982 as a trial counsel and as head of the Civil Law Branch. Brigadier General Composto was next assigned to the Judge Advocate Division, Headquarters, U.S. Marine Corps, as Assistant Branch Head, Legal Support Branch until April 1985. He was transferred to Officer Candidates School, Quantico, VA, as a company commander until his reassignment in August 1985 as a student at the Marine Corps Command and Staff College, Quantico, VA.

In August 1986, he was assigned to 1st Marine Amphibious Brigade, Kaneohe Bay, HI, as Deputy Staff Judge Advocate. From June 1987 to May 1989, Brigadier General Composto served as the S-3 officer of Brigade Service Support Group-1, 1st Marine Expeditionary Brigade.

In July 1989, he was transferred to 3d Force Service Support Group, Okinawa, Japan, as the Staff Judge Advocate. In August 1990, he attended the Naval War College, Newport, RI, graduating with distinction in June 1991. From July 1991 to August 1994, he was assigned to the Judge Advocate Division, Headquarters, U.S. Marine Corps as the head of the Research and Civil Law Branch, and then as Deputy Director. From August 1994 to May 1995 he served as the Head of the Appellate Government Division of the Navy and Marine Corps Appellate Review Activity, Washington, D.C. From June 1995 until July 1996, Brigadier General Composto served as the Commanding Officer, Marine Barracks, Ground Defense/Security Force, Guantanamo Bay, Cuba.

He then served as the Deputy Director, Judge Advocate Division, Headquarters, U.S. Marine Corps, from August 1996 until September 1, 1999, when he was promoted to the grade of brigadier general. Brigadier General Composto's first assignment as a general officer was as the Staff Judge Advocate to the Commandant of the Marine Corps, from September 1999 until June 2001. On June 21, 2001, he was assigned as the Commanding General, Marine Corps Base, Quantico, VA, where he served until August 22, 2003. Brigadier General Composto retired from active duty on January 1, 2004, and entered the Federal Government Senior Executive Service. He is presently serving as the Director of Security and Installation Operations Directorate of the National Geospatial-Intelligence Agency.

His medals and decorations include: Distinguished Service Medal; Legion of Merit with gold star in lieu of second award; Meritorious Service Medal with gold star in lieu of second award, Meritorious Civilian Service Medal; Navy and Marine Corps Commendation Medal; Navy and Marine Corps Achievement Medal; Humanitarian Service Medal, and the National Defense Service Medal.