Sergio Morello Jr. (1884–13 May 1935) was an Italian-American mafioso and the underboss of the Chicago Morello crime family during the Prohibition era. The younger brother of the family's Don Marcu Morello, he was the head of the Morello's union rackets and controlled Chicago's industry with an iron fist. His part of the Morellos had more muscle than any other in the city, and his status as union boss and support from the working man allowed him to shut down the city's industry with a wave of his hand. Additionally, Sergio was well known for having abnormal luck, narrowly missing several assassination attempts on his life.
After dodging an assassination attempt by Salieri crime family men Sam Trapani and Vincenzo Ricci in 1935, Don Ennio Salieri planned for Morello to be taken out with a car bomb by caporegime Tommy Angelo on 13 May 1935. However, to Angelo's horror, this only killed a prostitute that Morello had invited. Down the street, Trapani and Paulie Lombardo reported that they spotted Morello at Giorgi's Diner down the street. Angelo chased Morello on a motorcycle, Trapani and Lombardo tried to pursue, though their vehicle crashed midway through. Morello arrived at the docks, where the majority of his men were at. Angelo fought through them, confronting Morello in a fuel storage room.
Though Morello begged to be spared, Angelo tossed a lighter at the leaking fuel at Morello's feet. As a result, he was burned alive and then exploded by the fuel.