Felix got his start in animated shorts, beginning in Feline Follies in 1919. His creator, Otto Messmer, made the film in his spare time while working for Pat Sullivan. Because Messmer worked for Sullivan, Sullivan's name appears on the Felix products.
Felix's film career ended in 1931, but the character carried on in comic strip and comic book formats. A Sunday Felix strip was first published in 1923 and Messmer continued to draw it until 1943. In 1927, King Features began a daily strip drawn by artist Jack Bogle. The strip ran until 1967.
Felix never had his own radio show. He was recognized mainly through his animated short films and his daily cartoon strip. He did hit the television airways in the late 1960s as a Saturday morning cartoon offering.