Al Smith started his cartooning career at the New York World with the feature 'From 9 to 5'. In 1932 Wheeler and Bud Fisher contacted Smith about ghosting 'Mutt and Jeff'. After Fisher's death in 1954, Smith started to sign the strip himself. He also did the "topper" for the 'Mutt and Jeff' Sunday page, called 'Cicero's Cat'.
Besides drawing the 'Mutt and Jeff' strip, Smith was very active in the National Cartoonists Society for many years and helped a lot of young cartoonists starting their careers. Al Smith retired in 1980, leaving 'Mutt and Jeff' to George Breisacher. He died on November 24, 1986, in Vermont.