[4] Virgil W. Peterson of the Chicago Crime Commission stated that his "talents as an organizational genius were widely respected by the major gang bosses in the New York City area".

[7] When he was two his father, a railway employee, died in a work accident; shortly after, Torrio immigrated to James Street on the Lower East Side of New York City with his widowed mother in December 1884.

Torrio's gang ran legitimate businesses, but its primary concern was the numbers game, supplemented by incomes from bookmaking, loan sharking, hijacking, prostitution, and opium trafficking.

[10] One of Torrio's associates, Frankie Yale, eventually hired Capone to bartend at the Harvard Inn, a bar in the Coney Island section of Brooklyn.

"Big Jim" Colosimo, who had become head of a burgeoning vice empire in Chicago is reputed to have invited him to the city to help him deal with Black Hand extortionists.

[12] In 1919, Al Capone arrived in Chicago and started working as a bouncer and bartender at one of the Colosimo gang establishments, the Four Deuces at 2222 S. Wabash Street.

[12] Contract killer Frankie Yale had allegedly traveled from New York to Chicago and personally killed longtime gang boss Colosimo at the behest of Torrio.

[13] Torrio headed an essentially Italian organized crime group that was the biggest in the city, with Capone as his right-hand man.

[12] The smaller North Side Gang led by Dean O'Banion was of mixed ethnicity and was a member of the bootlegging cartel.

[12] Torrio would have immediately attempted to retaliate against O'Banion and the North Side Gang had it not been for Mike Merlo, head of the Unione Siciliana labor organization.

[12] O'Banion's death placed Hymie Weiss at the head of the North Side Gang, backed by Vincent Drucci and Bugs Moran.

He is credited with helping to organize a loose cartel of East Coast bootleggers, the Big Seven, in which many prominent gangsters, including Lucky Luciano, Longy Zwillman, Joe Adonis, Frank Costello, and Meyer Lansky played a part.

Torrio also supported the creation of a national body that would prevent all-out turf wars between gangs that had broken out in Chicago and New York.

His idea was well received,[24] and a conference was hosted in Atlantic City by Torrio, Lansky, Luciano and Costello in May 1929; the National Crime Syndicate was created.