John Lawrence Russell (January 3, 1921 – January 19, 1991) was an American motion picture film and television actor, and World War II veteran, most noted for his starring role as Marshal Dan Troop in the successful ABC western television series Lawman from 1958 to 1962. and his lead role as international adventurer Tim Kelly in the syndicated T.V. series Soldiers of Fortune from 1955-57 .