 Trofimoff enlisted in the United States Army in 1948 and received a commission in the United States Army Reserve in 1953.He received an honorable discharge from active duty in 1956, and retired from the United States Army Reserve with the rank of Colonel in 1987.From 1959 through 1994, Trofimoff was employed by the United States Army as a civilian working in military intelligence, serving primarily in the Kingdom of Laos and in West Germany.