List of Chicago criminal organizations and crime bosses explained

See main article: Timeline of organized crime in Chicago.

Participants in organized crime in Chicago at various times have included members of the Chicago Outfit associated with Al Capone, the Valley Gang, the North Side Gang, Prohibition gangsters, and others.

Chicago Outfit (Al Capone Gang)

(Formerly called the "Capone Gang".)

• Jim Colosimo, founder
• Johnny Torrio, foundational leader of American organized crime
• Al Capone, heir of American organized crime
• Frank Nitti
• Paul Ricca
• Tony Accardo

Valley Gang

• Paddy Ryan
• Terry Druggan
• Frankie Lake

Genna Crime Family

• Angelo Genna
• Mike Genna
• Pete Genna
• Jim Genna
• Sam Genna
• Tony Genna

North Side Gang

• Dion O'Banion
• Hymie Weiss
• Vincent Drucci
• George Moran

Chicago gang leaders

• Joey Aiello (Unione Siciliana takeover)
• Sam Cardinelli ("Black Hand" gang)

Prohibition gangs

• Roger Touhy (Des Plaines, Illinois)
• Ragen's Colts, founded as a baseball team by James M. Ragen on the South Side
• Southside O'Donnell's
• Westside O'Donnells, led by Myles O'Donnell and William O'Donnell
• Frank McErlane-Joe Saltis Gang

Racketeers

• Maurice Enright, Chicago labor racketeer