Frank Gusenberg (October 11th, 1893 – February 14th, 1929) was an American contract killer and a victim of the Saint Valentine's Day massacre in Chicago, Illinois.
He participated in the gargantuan drive-by shooting in the North Side performed on Capone's headquarters, the Hawthorne Hotel in Cicero, Illinois, riddling it with thousands of bullets on September 20th, 1926. According to many accounts, the second to last car stopped in front of the hotel restaurant where Capone was cowering and Gusenberg's brother Pete emerged, clad in a khaki Army shirt, brown overalls, and carrying a Thompson submachine gun fitted with a 100-round capacity drum. Kneeling in front of the doorway, Gusenberg emptied the entire drum into the restaurant, and then casually strolled back to his car, which then sped off to safety.
The attack worked. Capone was very shaken and requested a sitdown between the two gangs. However, it failed. Hymie Weiss was murdered three weeks later, and over the next couple of years, the North Side Gang continued to weaken. The North Siders especially wished to kill Jack McGurn, as he was rumored to have been the machine-gunner who killed Weiss. On at least two occasions, the Gusenberg brothers made attempts on his life. Despite receiving several wounds, McGurn survived these attempts. Al Capone had Pasquale "Patsy" Lolordo installed as head of the influential fraternal organization Unione Siciliane. By late 1928, the leader of the North Side Gang, Bugs Moran, struck an alliance with Al Capone's rival Joe Aiello. The latter, assisted by the Gusenberg brothers, killed Antonio Lombardo and Pasqualino Lolordo, presidents of the Unione Siciliane. It was as a result of these murders that Capone plotted to eliminate Bugs Moran.