Robert "Bob" Leffingwell was the brother of Ed Leffingwell, who created the 'Little Joe' Sunday page in 1933. He had succeeded his brother as the assistant of his cousin Harold Gray on 'Little Orphan Annie'. When Ed died in 1936, he continued 'Little Joe' for Tribune Media Services until the end of its run in 1972. He also did art for 'Little Orphan Annie' shortly after Gray's death in 1968, but the strip was eventually continued by Tex Blaisdell. In the 1930s, Leffingwell has also done comic book art for companies like Centaur ('Evidence Eddy', 'Taint So!') and National Periodicals ('It's A Dern Lie', 'Sagebrush 'n' Cactus', 'Sir Loin of Beef').