Mark Brown was commissioned a 2d Lt in the U.S. Air Force through the Air Force ROTC program at Tuskegee University in Tuskegee, Alabama, and went on active duty beginning July 24, 1986. After attending Accounting and Finance Officer training, Lt Brown served as Deputy Accounting and Finance Officer for the 3rd Tactical Fighter Wing at Clark Air Base in the Philippines from October 1986 to September 1988, followed by service as Accounting and Finance Officer for the 380th Bomb Wing at Plattsburgh AFB, New York, from October 1988 to October 1990. His next assignment was as Accounting and Finance Officer with the 401st Fighter Wing at Torrejon AB, Spain, from November 1990 to September 1992, and then as Chief of the Financial Analysis Branch with the 20th Fighter Wing at RAF Upper Hayford, England, from October 1992 to June 1994. Major Brown served as Commander and Regional Accounting and Finance Officer with the 32nd Accounting and Finance Squadron at Incirlik AB, Turkey, from July 1994 to September 1995, followed by service as Budget Analyst for the Flying Hour Program with Headquarters Air Combat Command at Langley AFB, Virginia, from October 1995 to June 1998. His next assignment was as Commander of the 7th Comptroller Squadron with the 7th Bomb Wing at Dyess AFB, Texas, from July 1998 to July 2000, and he then attended Air Command and Staff College at Air University, Maxwell AFB, Alabama, from August 2000 to June 2001. Lieutenant Colonel Brown served as Base Operations Support Budget Analyst with Headquarters U.S. Air Force in the Pentagon from July 2001 to February 2002, followed by service as Assistant Executive Officer to the Chief of Staff of the Air Force at the Pentagon from March 2002 to September 2003. His next assignment was as a Congressional Liaison at the Pentagon from October 2003 to July 2004, and he then attended National War College at Fort McNair, Washington, D.C., from August 2004 to June 2005. Colonel Brown served as a Congressional Liaison and then as Deputy Director of Budget and Appropriations Affairs with the Office of the Comptroller, Office of the Secretary of Defense, at the Pentagon from July 2005 to June 2006. His next assignment was as Senior Military Assistant for the Under Secretary of Defense Comptroller in the Pentagon from July 2006 to June 2007, followed by service as Commander of the 14th Mission Support Group at Columbus AFB, Mississippi, from July 2007 to July 2009. General Brown served as Comptroller at Headquarters Air Mobility Command at Scott AFB, Illinois, from August 2009 to October 2011, and then as Director of Financial Management at Headquarters Air Force Material Command at Wright-Patterson AFB, Ohio, from November 2011 to July 2014. He served as Commander of 2nd Air Force at Keesler AFB, Mississippi, from July 2014 to August 2016, and then as Vice Commander/Deputy Commander of Air Education and Training Command at Joint Base San Antonio-Randolph, Texas, from September 2016 until his retirement from the Air Force on June 1, 2018.