Donald J. Berg joined the Air Force in 1959. He was offered a regular commission as a 2nd lieutenant and was stationed at SAC, Columbus Air Force Base as an electronic warfare officer on B-52 bombers.

In response to the Cuban Crisis in 1962, he was assigned airborne alert, flying 24-30 hour "Chrome Dome" missions from the U.S. to Europe to the Mediterranean and back to the U.S.

In 1965, he was rotated to Andersen AFB, Guam where was part of the second Arc Light mission over
Vietnam. He was awarded the Air Medal for flying 15 Arc Light missions over Vietnam.

In 1970, he was assigned an 18-month tour of duty in Taiwan. He was the navigator or instructor navigator in C-130 airplanes flying missions around Southeast Asia.

In 1971, he was awarded the Distinguished Flying Cross for accomplishing an emergency airdrop of 32,000 pounds of critically needed fuel to a beleaguered outpost that was cut off from normal supply routes by three hostile troop concentrations of battalion size. He delivered the fuel in spite o{ heavy automatic weapons fire in the target area.

In 1975, he was awarded the Meritorious Service Medal for his outstanding technical skills resulting in major contributions to the analysis of future strategic forces.

In 1980, for exceptional meritorious service from August 1975 through April 1980, while assigned to the
Studies, Analysis and Gaming Agency (SAGA), an organization of the Joint Chiefs of Staff, he was awarded the Defense Meritorious Service Medal for developing new and innovative techniques for the use of computers in support of the analytic efforts of SAGA.

Other medals and citations awarded to him include the Air Force Commendation Medal, Combat Readiness Medal, Presidential Unit Citation, and Air Force Outstanding Unit Award. He was selected for colonel in 1979, and he retired in May, 1980.