Throughout his tour in Vietnam, Otis received the Distinguished Service Cross, Silver Star, and Purple Heart with Oak Leaf Cluster, the Legion of Merit, and eight Air Medals.

He also served as a member of the House Armed Services Committee's Commission to Assess United States National Security Space Management and Organization in 2000, which was chaired by Donald Rumsfeld.

[6][7] Citation: The Distinguished Service Cross is presented to Glenn K. Otis, Lieutenant Colonel (Armor), U.S. Army, for extraordinary heroism in connection with military operations involving conflict with an armed hostile force in the Republic of Vietnam, while serving with Headquarters Troop, 3d Squadron, 4th Cavalry, 25th Infantry Division.

Lieutenant [sic] Otis distinguished himself by exceptionally valorous actions on 31 January 1968 as commanding officer of a cavalry squadron defending against the communist Lunar New Year offensive at Tan Son Nhut Air Base.

Braving devastating rocket, machine gun and mortar fire, he repeatedly ordered low passes over the enemy positions to assess the rapidly changing situation and skillfully coordinate his unit's defenses.