Born in California, Peter was a long-time resident in San Francisco with wife Adonica. His first work for comic books was through Lloyd Jacquet's comic shop, Funnies, Inc., where he illustrated such features as the biography of General George Marshall in True Comics #4 (September 1941).
His most lasting work came when the 61-year-old artist brought William Moulton Marston's Amazonian superheroine Wonder Woman to life on the pages of comic books (even though Peter went on to be uncredited in her creation) in December 1941. In April 1942, he opened his own studio at 130 W. 42nd Street in Manhattan. Peter continued with Wonder Woman until his death in 1958.