He had his breakthrough role in October Sky, and won a BAFTA Award for Best Supporting Actor for his role in Brokeback Mountain. He also had memorable roles in The Day After Tomorrow, Zodiac, and Love and Other Drugs. His portrayal of Louis Bloom in the 2014 film Nightcrawler earned him a Golden Globe nomination for Best Actor in a Motion Picture, Drama.
He starred in the cult classic film, Donnie Darko, for which he won the 2003 Chlotrudis Award for Best Actor.
He is the godfather of Heath Ledger's daughter, Matilda.
He worked as a lifeguard and busboy as a teenager. In 1991, he debuted as Danny Robbins in City Slickers.
He is the brother of actress Maggie Gyllenhaal. His parents worked in Hollywood as directors and screenwriters.