Torrio, believed to have been a nephew of Big Jim Colosimo of Chicago and the son of a widowed mother, grew up in New York and was a member of Five Points gangs until heading across the river to a leadership position alongside gangster Frank Uale. Torrio had established himself as a big shot in Brooklyn by 1909, when his uncle called him west to help out with a Black Hand problem. Colosimo, who was NOT a Mafioso (the crime group which originated with Colosimo has never claimed to be "Mafia") and ran a string of brothels and entertainment establishments, was being victimized by extortionists. Torrio set about the tasks of eliminating the Black Hand threat and forming a gang to support the illicit operations of Uncle Jim.

By 1919, Torrio was Colosimo's right hand man. He still needed a ruthless enforcer and an opportunity presented itself. One of his old underlings from Brooklyn, Alphonse Capone, was wanted on murder charges in New York and would surely benefit from a change in scenery. Torrio sent for Capone and put him to work as a bouncer. Capone, who had always showed a knack for thuggery, became extremely valuable to Torrio on the violent streets of Chicago.

At the time, a Mafia organization run by the Genna Brothers was competing with a North Side gang of Jewish and Irish immigrants and other smaller elements around the town. Colosimo's organization was not set up along the same lines, but it would soon change. Colosimo was killed on May 11, 1920. It is generally accepted that Frank Uale was the triggerman. Uale's previous relationships with Torrio and Capone, and the fact that Torrio was the obvious beneficiary of the assassination have caused many to charge that Torrio ordered the killing.

That may very well be. But it is also possible that the Gennas, who were strongly connected with Uale through the Unione Siciliana (which was led nationally by Uale beginning in 1918), had ordered the hit. Colosimo's vice organization was certainly intruding on Mafia territory and becoming a threat to the Genna's organized bootlegging operations in Chicago's Little Italy communities.

After taking power, Torrio attempted to make peace with his neighbors and establish zones of influence for the various gangs within the city and its suburbs. In 1923, the gang's move into Cicero required careful negotiations with the mobsters and politicians already in that community.

The peace in Chicago was an uneasy one and was broken permanently in 1924 when Torrio was betrayed by North Siders who sold him the Sieben Brewery and then had police raid the establishment shortly thereafter. Torrio was sentenced to a prison term, but before he was sent away, rival gangsters decided to try to send him to the morgue. He was shot and severely wounded at his home Jan. 24, 1925. As he lay in the hospital, he reportedly turned command of his organization over to Capone and officially retired.

Torrio would no longer directly participate in the Chicago underworld, but he would still be an influential character on the national (and perhaps international) scene. After recovering from his injuries and serving his prison sentence, Torrio headed out on the road. He repeatedly visited New York and also went abroad. In New York, he worked closely with the likes of Charlie Luciano and Frank Costello and may have been one of the architects of the cooperative bootlegging organization known as the Seven Group.

It is believed that Torrio played an elder statesman's advisory role as organized crime units from around the country assembled into a national Syndicate in the early 1930s.