Milano is the daughter of Lin, a fashion designer and talent manager, and Thomas M. Milano, a film music editor. She is of Italian ancestry. Milano was born in Bensonhurst, Brooklyn and lived there until a neighborhood shooting prompted the family to relocate to Staten Island. She has a younger brother, Cory (b. 1982), who is also an actor. In a 2003 interview, Milano recalled having had a good childhood, having grown up in a "loving, true family." Having grown up in front of the camera, Milano did not feel that it jeopardized her childhood: "I love my family very much - they've really backed my career. I consider myself to be normal: I've got to clean my room, and help in the kitchen."