During World War II, Silliphant served as a lieutenant in the United States Army. Upon his discharge in 1946 in the earlier part of his career, he was publicity director for Walt Disney, and was lead writer on the stories incorporated into "The Mickey Mouse Club". He produced several independent films such as "5 Against the House" with Kim Novak, "Huk!" and "Maracaibo". Later he broke into television, writing for the live "Playhouse 90". "Perry Mason" and "Alfred Hitchcock Presents" soon followed.