Jacob Benjamin Gyllenhaal was born on December 19, 1980, in Los Angeles, California, United States, to screenwriter Naomi Foner and film director Stephen Gyllenhaal. Actress Maggie Gyllenhaal, his older sister, appeared with him in the science fiction psychological thriller film Donnie Darko (2001). Gyllenhaal's father, who was raised as a Swedenborgian, is a Christian of Swedish and English descent and is a descendant of the Swedish noble Gyllenhaal family. His last ancestor to be born in Sweden was his great-great-grandfather, Anders Leonard Gyllenhaal. Gyllenhaal's mother is Jewish, and was born in New York City into an Ashkenazi Jewish family from Russia and Poland. Gyllenhaal has said that he considers himself Jewish. Gyllenhaal was born with a lazy eye and has been wearing corrective lenses since he was 6. On his 13th birthday, Gyllenhaal performed a "Bar Mitzvah-like act, without the typical trappings", volunteering at a homeless shelter because his parents wanted to give him a sense of gratitude for his privileged lifestyle.
As a child, Gyllenhaal was regularly exposed to filmmaking due to his family's ties to the industry. He made his acting debut as Billy Crystal's son in the 1991 comedy City Slickers. His parents did not allow him to appear in The Mighty Ducks (1992) because it would have required him to leave home for two months. In subsequent years, his parents allowed him to audition for roles but regularly forbade him to take them if he were chosen. He was allowed to appear in his father's films several times. Gyllenhaal appeared in 1993's A Dangerous Woman (along with sister Maggie), in "Bop Gun", a 1994 episode of Homicide: Life on the Street; and in the 1998 comedy Homegrown. Along with their mother, Jake and Maggie appeared in two episodes of Molto Mario, an Italian cooking show on the Food Network. Prior to his senior year in high school, the only other film not directed by his father in which Gyllenhaal was allowed to perform was the 1993 film Josh and S.A.M., a little-known children's adventure.
His parents insisted that he have summer jobs to support himself, and he thus worked as a lifeguard and as a busboy at a restaurant operated by a family friend. Gyllenhaal said his parents encouraged artistic expression: "I do have parents who constantly supported me in certain ways. In other ways, they were lacking. Definitely, it's in expression and creativity where my family has always been best at." Gyllenhaal graduated from the Harvard-Westlake School, a private school in Los Angeles in 1998, then attended Columbia University, where his sister was a senior and from which his mother had graduated, to study Eastern religions and philosophy. At Columbia, he was a resident of John Jay Hall. Gyllenhaal dropped out after two years to concentrate on acting but has expressed intentions to eventually finish his degree. Gyllenhaal's first lead role was in October Sky, Joe Johnston's 1999 adaptation of the Homer Hickam autobiography Rocket Boys, in which he portrayed a young man from West Virginia striving to win a science scholarship to avoid becoming a coal miner. The film was positively received and earned $32 million; it was described in the Sacramento News and Review as Gyllenhaal's "breakout performance".
