Known as "Rudy" to friends and family, Wanderone started playing pool as a child while living in Washington Heights, Manhattan. In 1923, he traveled with his father to Europe, where he received training from German balkline billiards champion Erich Hagenlocher. His first prominent match was in 1926, when he competed against former nine-ball champion "Cowboy" Weston; Wanderone won, handily. Wanderone left school in the eighth grade and became a traveling pool hustler, spending much of the 1920s playing at a pool hall called Cranfield's in New York City, where he received his first nickname after beating another hustler known as "Smart Henry". The intensity of their competition led Wanderone's friend Titanic Thompson to dub Wanderone "Double-Smart". By the mid-1930s, during the Great Depression, Wanderone had become a manager of a pool hall, owned by a friend, in Anacostia, southeast Washington, D.C. He had acquired more notoriety and nicknames, including "Triple-Smart Fats", "New York Fats", "Broadway Fats", and "Chicago Fats", attracting from other hustlers, including the then-unknown Luther "Wimpy" Lassiter.