Sylvester Gardenzio Stallone[5][6][7] was born in the Hell’s Kitchen neighborhood of New York City’s Manhattan borough[8] on July 6, 1946,[9] the elder son of women’s professional wrestling promoter Jacqueline “Jackie” Stallone (née Labofish; 1921–2020) and hairdresser Francesco “Frank” Stallone Sr. (1919–2011). His mother was an American from Washington, D.C. with Breton French[11] and Ukrainian Jewish ancestry, while his father was an Italian immigrant from Gioia del Colle[10] who moved to the U.S. in the 1930s.[15][16] His younger brother is actor and musician Frank Stallone.[10] Many biographies of Stallone indicate that his birth name is “Michael Sylvester Gardenzio Stallone” and his mother explained in an interview that she originally named him “Tyrone” because she admired the actor Tyrone Power, but Stallone’s father changed it to “Sylvester”. His nickname as a child was “Binky” but he chose to go by the nickname of Mike/Michael after schoolmates began calling him “Stinky”.[5][6][7] His middle name “Gardenzio” is an alteration of the Italian given name “Gaudenzio” and he usually shortened it to “Enzio”.

Complications during Stallone’s birth forced his mother’s obstetricians to use two pairs of forceps while delivering him, accidentally severing a nerve in the process.[17][18] This caused paralysis of the lower left side of his face (including parts of his lip, tongue, and chin) which gave him his signature snarling look and slurred speech.[18][19] As a result, he was bullied in his childhood, with which he coped by getting into bodybuilding and acting.[20] He spent part of his infancy in foster and boarding care, rejoining and moving back with his family to Maryland when he was five. In the early 1950s, his father moved the family to his mother’s native Washington, D.C. to open a beauty school. In 1954, his mother opened a women’s gym called Barbella’s. He initially stayed with his father following his parents’ divorce when he was 11, but joined his remarried mother in Philadelphia when he was 15.