Michael Gerard Tyson was born in Brownsville, Brooklyn, New York, on June 30, 1966. He has an elder brother named Rodney (born c. 1961) and had an elder sister named Denise, who died of a heart attack at age 24 in February 1990.
Tyson's biological father is listed as "Purcell Tyson" (who was from Jamaica) on his birth certificate, but the man Tyson had known as his father was Jimmy Kirkpatrick. Kirkpatrick was from Grier Town, North Carolina (a predominantly black neighborhood that was annexed by the city of Charlotte), where he was one of the neighborhood's top baseball players. Kirkpatrick married and had a son, Tyson's half-brother Jimmie Lee Kirkpatrick, who would help to integrate Charlotte high school football in 1965. In 1959, Jimmy Kirkpatrick left his family and moved to Brooklyn, where he met Tyson's mother, Lorna Mae (Smith) Tyson. Kirkpatrick frequented pool halls, gambled and hung out on the streets. "My father was just a regular street guy caught up in the street world", Tyson said. Kirkpatrick abandoned the Tyson family around the time Mike was born, leaving Tyson's mother to care for the children on her own. Kirkpatrick died in 1992.
The family lived in Bedford-Stuyvesant until their financial burdens necessitated a move to Brownsville when Tyson was 10 years old. Tyson's mother died six years later, leaving 16-year-old Tyson in the care of boxing manager and trainer Cus D'Amato, who would become his legal guardian. Tyson later said, "I never saw my mother happy with me and proud of me for doing something: she only knew me as being a wild kid running the streets, coming home with new clothes that she knew I didn't pay for. I never got a chance to talk to her or know about her. Professionally, it has no effect, but it's crushing emotionally and personally."
Throughout his childhood, Tyson lived in and around neighborhoods with a high rate of crime. According to an interview in Details, his first fight was with a bigger youth who had pulled the head off one of Tyson's pigeons. Tyson was repeatedly caught committing petty crimes and fighting those who ridiculed his high-pitched voice and lisp. By the age of 13, he had been arrested 38 times. He ended up at the Tryon School for Boys in Johnstown, New York. Tyson's emerging boxing ability was discovered there by Bobby Stewart, a juvenile detention center counselor and former boxer. Stewart considered Tyson to be an outstanding fighter and trained him for a few months before introducing him to Cus D'Amato. Tyson dropped out of high school as a junior. He would be awarded an honorary Doctorate in Humane Letters from Central State University in 1989. Kevin Rooney also trained Tyson, and he was occasionally assisted by Teddy Atlas, although Atlas was dismissed by D'Amato when Tyson was 15. Rooney eventually took over all training duties for the young fighter.