Colonel David Osborne entered the Army as a private of Infantry in 1981. After being selected as the Distinguished Honor Graduate from his OSUT class, he was selected for Officer Candidate School. He was commissioned an Infantry Officer upon graduation from OCS class 5-82 at Fort Benning, Georgia, 10 November 1982. His first duty assignment was as a platoon leader, 3-187th Infantry, 101st Airborne Division (Air Assault).

His subsequent duty assignments were: Maintenance Officer in HHC, Executive Officer, C Co and D Co (anti-armor), 3-187th Infantry. Following degree completion, he was assigned to the 3rd U.S. Infantry (The Old Guard). He served as Assistant S3, Company Commander, where he received the MacArthur Leadership Award, then Deputy S3 and subsequently selected as the aide de camp to the commanding general.

Following CGSC he was assigned to Germany where he served as an action officer in V Corps G-3 Ops, then battalion S-3 of 1-15th Infantry both in Germany and Macedonia. Upon return he was the 0-3 of the Grizzly O/C team in Hohenfels. After a tour as a plans officer at Supreme Headquarters Allied Powers Europe (SHAPE) in Belgium, COL Osborne assumed command of 3-1 Infantry at Fort Benning, the Army's only active duty Officer Candidate School. After attending the Army War College, he was assigned to the Army Initiatives Group (AIG), Army G-3. His final assignment was as the Chief, Army Leader Development Division, Army G-3.

His military education includes: United States Army Officer Candidate School, Infantry Officer Basic and Advanced Courses, Command and General Staff Officer College, Armed Forces Staff College, and the Army War College.

COL Osborne's highest military awards include: Legion of Merit, Defense Meritorious Service Medal, Meritorious Service Medal (4th Award), Army Commendation Medal (6th Award), Army Achievement Medal (8th Award), Good Conduct Medal, Joint Meritorious Unit Award (2nd Award) the United Nations Medal and the Order Of Saint Maurice (Centurion).