He was born to a Russian Jewish family in Königsberg, then in East Prussia.
His parents died during World War II in concentration camps.
On 14 August 1953 he became an American citizen,[1] but in 1958 he moved to Munich where he lived for the rest of his life.
Among other writings, he wrote for the Münchner Lach- und Schießgesellschaft, a cabaret theatre founded by Sammy Drechsel and Dieter Hildebrandt.
[2] In Los Angeles, Colpet lived in the guest house behind Wilder's Beverly Hills house, 704 North Beverly Drive, until Wilder sold the house to Dr. Harry Lehrer and fashion designer Anne T. Hill in 1957 and moved to Century City.