An animator at Warner Brothers beginning in 1932, McKimson became a director of cartoons in 1946 with Daffy Duck's memorable descent into criminal graffiti, Daffy Doodles. He remained at Warners until its cartoon unit folded in 1963. Over the years he made many clever cartoons, working with such established icons as Bugs Bunny (Hurdy Gurdy Hare) and Porky Pig (One Meat Brawl), and creating such beloved characters as Foghorn Leghorn (A Fractured Leghorn) and the Tasmanian Devil (Devil May Hare). From the mid '60s until his death in 1977, McKimson worked at DePatie-Freleng Enterprises.