Jacob "Jake" Gyllenhaal (last name pronounced jill-en-hall) was born in Los Angeles, California, on December 19, 1980 to director Stephen Gyllenhaal and producer/screenwriter Naomi Foner, and is the brother of actress Maggie Gyllenhaal, who played his sister in Donnie Darko. His father is of partial Swedish heritage and his mother is of Ashkenazi Jewish heritage.

Jake made his film debut at age eleven in City Slickers playing Billy Crystal's son and began to establish himself as an up-and-coming actor in films like as October Sky before being cast in the title role in Donnie Darko, for which he was nominated for an Independent Spirit Award for best actor. Gyllenhaal's performance as a troubled psychotic won him excellent reviews, and the film quickly received cult status. He played opposite Jennifer Aniston in another Sundance favorite in The Good Girl and once again earned good reviews. Gyllenhaal also starred in the Walt Disney romantic comedy, Bubble Boy and in the science fiction blockbuster The Day After Tomorrow which also starred Dennis Quaid.

Making his theater debut, Gyllenhaal appeared on the London stage with a starring role in Kenneth Lonergan's revival of This Is Our Youth. The play, which had been a critical sensation on Broadway, ran for eight weeks in London's West End. Gyllenhaal's performance in Jarhead with Jamie Foxx came as a surprise to critics and fans alike. Gyllenhaal played a markedly hostile, masculinely violent Marine during Gulf War I, while balancing this with the sensitive, vulnerable qualities of the lead character. Brokeback Mountain, in which he co-starred with Australian actor Heath Ledger as sheep herders who fall in love in the 1960s and depicts their relationship over the 1960s, 1970s and early 1980s. The film went on to win four Golden Globes, four BAFTA Awards and was nominated for a leading eight Academy Award nominations including Best Picture and Best Supporting Actor for Gyllenhaal was nominated for an Academy Award in the category of Best Supporting Actor for his performance in Brokeback Mountain. Jake is also the godfather of Matilda Rose Ledger, daughter of actor Heath Ledger and Michelle Williams,

Gyllenhaal's most notable relationship has been with actress Kirsten Dunst. He is friends with Maroon 5 front-man Adam Levine, having known him since kindergarten. He is close with his sister's boyfriend and Jarhead co-star, actor Peter Sarsgaard. Jake has two dogs: a German Shepherd named Atticus and a Puggle named Boo Radley after the characters of his favorite book, To Kill A Mockingbird.

Gyllenhaal's career is booming and he is considered one of the most promising actors of his generation.
Jarhead (2005): $3,000,000
Dropped out of Columbia University after two years (2002). Son of director Stephen Gyllenhaal and screenwriter Naomi Foner. Younger brother of Maggie Gyllenhaal. His godmother is Jamie Lee Curtis and godfather is Paul Newman. He received his first driving lesson from Newman. Graduated Harvard-Westlake (private) high school. [1998] Is of Swedish (noble) and Russian-Jewish descent. Played brother to real life sister Maggie Gyllenhaal in their movie Donnie Darko. Received his first driving lesson from Paul Newman. His fans refer to themselves as "Gyllenhaalics". His last name is pronounced Jill-en-hall. Sister Maggie Gyllenhaal introduced him to Kirsten Dunst. Both Kirsten and Maggie appeared in Mona Lisa Smile. Jake and Kirsten dated, but broke up in July 2004. He was awarded the 2002 London Evening Standard Theate Award for Outstanding Newcomer for his performance in This is Our Youth at the Garrick Theatre in London, England. Was set to play Spiderman in Spider-Man 2 due to complications with Tobey Maguire. While he was preparing for the role, Maguire was back as Spiderman. Attended high school with Freaks and Geeks star Jason Segel. Was named one of People Magazine's 50 Hottest Bachelors [2004]. Is close friends with Natalie Portman and Bryce Dallas Howard. Went to elementary school with band members of Maroon 5. On Phantom Planet's album "The Guest", lead singer Alex Greenwald lists him in his thank yous. Alex appeared with Jake in Donnie Darko. His favorite book is To Kill a Mockingbird, and he has two dogs, Atticus and Boo named after the novel's main characters. Auditioned for and was one of the top contenders for the role of Batman/Bruce Wayne in Batman Begins. Shares his birthday with Marla Sokoloff, Alyssa Milano, Jennifer Beals and Édith Piaf. Before success as an actor, he worked as a lifeguard. He never had any life-saving incidents, but did perform one lesser rescue. A swimmer had been stung on the leg by a jellyfish, and Gyllenhaal helped relieve the pain of the stings by urinating on the swimmer's leg. Godmother is Jamie Lee Curtis. Although they broke up in July 2004, he and Kirsten Dunst still have an on and off relationship. Gained five pounds of muscle for his role in Jarhead. When asked who his idols are he said Anthony Quinn, Paul Newman, Sean Penn, Bruce Springsteen and Bono. Spent two years at Columbia University, where one of his professors was Robert Thurman, Uma Thurman's father. Godfather of Matilda Rose Ledger, born October 28, 2005 (daughter of actor Heath Ledger and actress Michelle Williams. Was among the guests at Jessica Simpson's 25th birthday party. He gave Kirsten Dunst a gray and white kitten for her birthday. She named the cat Sophie. Ranked #48 on Premiere's 2006 "Power 50" list. It is his first appearance on the list. His first four big roles were in movies with alliterated titles: Bubble Boy, Donnie Darko, Moonlight Mile, The Good Girl. Invited to join AMPAS in 2006. Studied acting with Ivana Chubbuck. Along with sister, Maggie Gyllenhaal, he attended Camp Walt Whitman, an outdoors summer camp in Western New Hampshire. Uncle of Ramona Sarsgaard, born October 3, 2006. She is the daughter of his older sister Maggie Gyllenhaal and Peter Sarsgaard. His uncle, Anders Gyllenhaal, is editor-in-chief of the Star Tribune newspaper in Minneapolis. Godfather is Paul Newman. Is good friends with Lance Armstrong and Matthew McConaughey. Like all Gyllenhaals on the male line, he is a Swedish nobleman by birth right and is listed in the Swedish Almanac of Nobility ("Sveriges Ridderskaps och Adels Kalender" in Swedish). Campaigned for the Democrats in the 2004 US election. As of 2007, has starred in three movies where he played not only a real person, but the person who wrote the book upon which the film was based: Homer Hickham (October Sky), Anthony Swofford (Jarhead) and Robert Graysmith (Zodiac). Voted #10 in Elle (France) Magazine's "15 Sexiest Men" poll (June 2007).