Daniel John Patrick Greene was an American mobster in Cleveland, Ohio, whose conflicts with the Cleveland crime family of the Italian-American Mafia ended in Greene's murder in 1977.

The Cleveland crime family, also known as the Scalish crime family or the Cleveland Mafia, is an Italian American Mafia crime family based in Cleveland, Ohio and throughout the Greater Cleveland area. The organization formed during the 1900s, as leadership turned over frequently due to a series of power grabs and assassinations. In 1930, Frank Milano became boss and was able to bring some stability to the family. Under the control of the family's longest-serving boss, John T. Scalish, who led the organization from 1945 until 1976, the Cleveland Mafia exerted influence over the Teamsters union, profiting from labor racketeering and the skimming of revenue from Las Vegas casinos.