He then attended Air Intelligence Officers School, and served at Westover AFB, Mass., where, among his other activities, he taught undergraduate political science courses at American International College. After becoming fluent in the Vietnamese language at Sanz Language School, in Washington, D.C, he was assigned to Vietnam in 1967as an intelligence officer.  

In Vietnam, he was responsible for the deployment and operations of six intelligence teams operating from a number of sites, including Saigon, Bien Hoa, Nha Trang, Pleiku, Da Nang and Can Tho. The teams were involved with significant intelligence operations, particularly involving the attack on Tan Son Nhut Air Base during the Tet Offensive of 1968, and the defense of the Marines and South Vietnamese at the Battle of Khe Sanh. 

Returning to the United States in May 1968, Bush was again assigned to Headquarters Air Force Special Projects Production Facility, at Westover AFB, as chief, Technical Analysis Division. He resumed teaching political science courses at American International College.  

In 1970, Bush resigned his commission, then attended Harvard Business School, majoring in Finance. He spent the rest of his professional career in numerous business enterprises, serving as manager and senior corporate executive in such companies as Merrill Lynch-White Weld Capital Group, Max Factor, and Hughes Electronics.