He served as a major in the United States Army, Allied Military Government, with service in Africa and Europe from 1943 until he was injured. He returned to the United States as an instructor at Fort Custer, Michigan, in 1945. He was employed with the Veterans' Administration at Muskogee, Oklahoma, in 1945 and 1946. Cartwright was elected Secretary of State of Oklahoma for four-year term in 1946. Cartwright was elected State auditor for four-year term in 1950. Cartwright was elected State corporation commissioner for six-year term in 1954 and reelected in 1960 and 1966. He was a resident of Oklahoma City, Oklahoma until his death there on March 14, 1979. He was interred in I.O.O.F. Cemetery, Norman, Oklahoma.