Major John Anthony Brown was commissioned an Air Defense Artillery Officer upon graduation from Officer Candidate School Class 1-92 at Fort Benning, Georgia on 30 January, 1992. His first duty assignment was as Platoon Leader, Battery A, 1st Battalion, 62nd Air Defense Artillery, 25th Infantry Division, Schofield Barracks, Hawaii.

His subsequent duty assignments include Assistant S2, 1-62nd Air Defense Artillery Battalion, Schofield Barracks, Hawaii; Battalion S2, 1-62nd Air Defense Artillery Battalion, Schofield Barracks, Hawaii; Executive Officer, 1-62nd Air Defense Artillery Battalion, Schofield Barracks, Hawaii; All Source Chief, 103rd Military Intelligence Battalion, Fort Stewart, Georgia; Assistant S3, 2nd Battalion, 363rd Regiment, Camp Parks, California; and Deputy Combined Joint, Combined Joint Tactical Force-10, Kandahar, Afghanistan. His last duty assignment was served as Intelligence Officer, 416th Theater Engineer Command, Darien, Illinois.

His military education includes: Air Defense Officer Basic Course, Air Defense Officer Short Range Air Defense Course, Military Intelligence Transition Course, Military Intelligence Advance Course, Airborne School, and Air Assault School.

His highest military awards include: Bronze Star Medal, Meritorious Service Medal, and Army Commendation Medal (2nd Award).

Major Brown joined the Federal Bureau of Investigation in 1999 as a special agent first assigned to the Chicago Field Office. He has deployed to Iraq as a member of a FBI team working counterterrorism with the Department of Defense. He rose through the ranks to assume the role of Special Agent in Charge of Cyber and Counterintelligence in the Los Angeles Field Office and Special Agent in Charge of the San Diego Field Office. He is currently serving as the Assistant Director, Senior Executive Service, Counter Intelligence at the Federal Bureau of Investigation.