O’Banion was the Renaissance man of crime, a professional singer who was a talented pickpocket and safe-cracker. But the great love of O’Banion’s life was floral arrangement, for which he had a passion and talent. In the halcyon days of gangland, it was customary to send flowers to the funeral of a man you shot, and O’Banion supplied the goods for most of the underworld’s needs. In was at his flower shop that he ran his gang, and it was at the flower shop, while working late at night on arrangements needed for the next morning, that he was assassinated by Mike Genna, and the famous assassins, Scalisi and Anselmi, in November, 1924., at the behest — or at least with the indifference of — Al Capone and Johnny Torrio. O’Banion was Torrio’s North Side operative, but was restless and eventually betrayed Torrio to the police in an elaborate scheme. It was O’Banion who coined the famous gangland phrase, “To Hell with the Sicilians.” Men like O’Banion did not last long in those days. After his death, O’Banion’s gang was later led by Bugs Moran, who moved the headquarters north to a garage on N. Clark Street, the site of the famous St. Valentine’s Day Massacre.
Despite the value of this property, located in Chicago’s Gold Coast just two blocks from the tourist meccas of N. Michigan Ave., the location of O’Banion’s flower shop is a strangely nearly empty block which serves largely as a parking lot for the Holy Name Cathedral, the seat of the Roman Catholic Archdiocese in Chicago, which was built in 1874. O’Banion had served in this church as a choir boy, and due to his infamy, the rector refused to allow his funeral service to be held there.
He was a childhood friend and, later, right-hand man of Dion O’Bannion. Moran and Earl (“Hymie”) Weiss inherited O’Bannion’s gang in Chicago when the chief was killed in 1924. Moran became sole leader after Weiss was killed in late 1926. For the next three years Moran’s gang and Al Capone’s were locked in bloody warfare, climaxed in 1929 by the St. Valentine’s Day Massacre, in which several members of Moran’s mob were slaughtered in a garage. (Moran narrowly avoided being killed. As he neared the building, he saw a police car arrive; unbeknownst to him, the men inside were actually associates of Capone. Thinking it was a raid, Moran immediately left.) His power reduced, he drifted into petty crimes, ending his days in prison for bank robberies (Ohio Penitentiary, 1946–56; Leavenworth federal penitentiary, 1957). He died of lung cancer.