The Chicago Outfit also known as Colosimo Outfit is a criminal organization operating out of Chicago founded by Giacomo Colosimo. It was distinct from the Five Families of New York and Al Capone took control of it in the mid-1920s.
The Outfit was initially kept out of the Commission, due to their reputation for violence. However, the Five Families in New York had agreed that everything west of Chicago belonged to the Outfit, with the exception of Las Vegas, which was declared an open city.
In 1932, when Capone was arrested for tax evasion, the business was taken over by Paul Ricca while Frank Nitti was acting as his front.
When Ricca stepped down in 1947, Louie Russo replaced him as boss, who managed to gain a seat on the Commission in the mid 1950s. After Russo was killed during an incident with Tom Hagen, he was succeeded by John Villone.[1]
In the 1950s, the Outfit invested heavily in Las Vegas by using the Teamsters' pension fund and made millions of dollars by skimming casinos over the course of several decades.