Cruise was born in Syracuse, New York, the son of Mary Lee (née Pfeiffer), a special education teacher, and Thomas Cruise Mapother III, an electrical engineer, both originally from Louisville, Kentucky. He has three sisters: Lee Anne, Marian, and Cass. They are of English, German, and Irish ancestry. One of Cruise's paternal great-great-great-grandfathers, Patrick Russell Cruise, was born in north County Dublin in 1799; he married Teresa Johnson in County Meath, in 1825. They left Ireland for the United States that same year and settled in New York. They had a daughter, Mary Paulina Russell Cruise, whose son Thomas Cruise Mapother was Cruise's great-grandfather. A cousin, William Mapother, is also an actor; he and Cruise have appeared in five films together.
Cruise grew up in near poverty, and had a Catholic upbringing. The family was dominated by his abusive father, whom Cruise has described as "a merchant of chaos." Cruise has said that he was beaten by his father, whom he has called a "bully and coward." He stated, "He was the kind of person where, if something goes wrong, they kick you. It was a great lesson in my life—how he'd lull you in, make you feel safe and then, bang! For me, it was like, 'There's something wrong with this guy. Don't trust him. Be careful around him.'"
Cruise spent part of his childhood in Canada. His family moved to Beacon Hill, Ottawa, in late 1971 so that Cruise's father could take a position as a defense consultant with the Canadian Armed Forces. There, Cruise attended the newly opened Robert Hopkins Public School for much of grade four and grade five. In grade four, Cruise first became involved in drama, under the tutelage of George Steinburg. Cruise and six other boys put on an improvised play to music called IT at the Carleton Elementary School drama festival. Drama organizer Val Wright, who was in the audience that night, reflected, "The movement and improvisation were excellent. It was a classic ensemble piece." Cruise also enjoyed sports at the school and played floor hockey, though he was known more for his aggression than his talent.
In sixth grade, Cruise went to Henry Munro Middle School in Ottawa, Canada. However, in the spring of that year, Cruise's mother left his father, taking Cruise and his sisters back to the United States. His father died of cancer in 1984. Cruise briefly attended a Franciscan seminary in Cincinnati, Ohio, on a church scholarship and aspired to become a Catholic priest, before his interest in acting.:24–26 In his senior year, he played for the varsity team as a linebacker, but he was cut from the squad after getting caught drinking beer before a game.:47 In total, Cruise attended 15 schools in 14 years, including stints in at least two suburban New Jersey towns, including Glen Ridge.