He was invited to Warner Bros. in 1933 along with fellow Disney animator Tom Palmer to head up the studio in the wake of Hugh Harman and Rudolf Ising's departure. In the event, Duvall was delayed working on other projects at Disney, and by the time he got to Warner Bros. Palmer had already been fired and replaced by Friz Freleng. During his time there, Duvall directed a number of cartoons based around surprisingly adult themes, and was allowed to direct the studio's first color cartoon, Honeymoon Hotel in 1934. Duvall died in 1969, the same year as the last Looney Tunes cartoon was released.