Jacob Benjamin Gyllenhaal (born December 19, 1980) is an American actor and producer. Born into the Gyllenhaal family, he is the son of director Stephen Gyllenhaal and screenwriter Naomi Foner; his older sister is actress Maggie Gyllenhaal. He began acting as a child, making his acting debut in City Slickers (1991), followed by roles in his father's films A Dangerous Woman (1993) and Homegrown (1998). His breakthrough roles were as Homer Hickam in October Sky (1999) and as a psychologically troubled teenager in Donnie Darko (2001).
In 2004, Gyllenhaal starred in the science fiction disaster film The Day After Tomorrow. In 2005, he played Jack Twist in Ang Lee's romantic drama Brokeback Mountain, for which Gyllenhaal won a BAFTA Award and was nominated for an Academy Award. His career progressed with starring roles in the thriller Zodiac (2007), the romantic comedy Love & Other Drugs (2010), and the science fiction film Source Code (2011). Further acclaim came with his roles in Denis