Colonel David Marshall, CD, enrolled in the Canadian Forces in 1975 under the Officer Candidate Training Plan. On completing his Artillery Officer Training at Gagetown, he served with 1 Airborne Battery, Royal Canadian Artillery (RCHA), which later became E Battery (Para) 2 Royal Canadian Horse Artillery. After a full tour of regimental duty, he was posted to the Canadian Forces Officer Candidate School in Chilliwack for two years as an Instructor. In 1982, he was posted to 1 RCHA in Lahr, Germany for a four year regimental tour culminating as Operations Officer.
Upon his return to Canada in 1986, Col Marshall attended the Canadian Land Forces Command and Staff College (CLFCSC) in Kingston. Following that assignment, he served as G3 staff officer in Special Service Force Headquarters in Petawawa. In 1987, he was posted to the Headquarters Canadian Forces Base Petawawa, as the Base Personnel Services Officer.
Col Marshall was seconded to the British Army in Germany in 1988, and commanded 127 (Dragon) Field Battery, 49 Field Regiment RA. During his tour as a Battery Commander, he deployed his battery on three operational tours, including a seven month active duty tour in the Persian Gulf. There he conducted combat operations with the Third Battalion, Royal Regiment of Fusiliers, as part of the 1st (UK) Armoured Division operations in Iraq and Kuwait. Returning to Canada in 1991, Col Marshall attended the Canadian Forces Command and Staff College in Toronto. Following his studies, he was posted to Land Forces Command Headquarters as the G1. In 1993 he was posted to Canadian Forces Base Petawawa as the Base Administrative Officer. From 1994 to 1996 he commanded the 2nd Regiment Royal Canadian Horse Artillery in Petawawa.
After completing French language training, Col Marshall became a member of the Directing Staff and later the Dean of Studies at the CLFCSC in Kingston. In 2001 he attended the Royal Military College where he received his BMASc. Upon completion of his studies, Col Marshall was appointed as Deputy Force Commander and Chief of Staff for a one year operational tour with UNDOF in the Golan Heights. In 2003, he was posted to his current position as Director of Staff, Allied Land Component Command Headquarters, Heidelberg, Germany. During his tour, he deployed to Iraq as the Special Advisor to the Deputy Commanding General, NATO Training Mission – Iraq.
Col Marshall was appointed to his current position as the Chief of Staff to Chief of Defence Intelligence in July 07.