By 1936, at age 24, Daddano had accumulated an extensive criminal record in the 42-Gang, including nine counts of bank robbery, larceny and auto theft. Giancana and Battaglia eventually recruited Daddano into the Chicago Outfit. In 1944, Daddano was arrested for attempting to steal three million war ration stamps. While police suspected that the Outfit was behind this crime, Daddano refused to name his accomplices. After World War II, Daddano became a leading enforcer for The Outfit. He also controlled illegal gambling operations in Dupage, Will and Kane counties and in the Chicago suburbs of Cicero and Berwyn.