Well, to make a long story short, Jake Gyllenhaal is Jewish!
Since Jake Gyllenhaal's mother is Jewish, and in Orthodox Judaism and Conservative Judaism, those with a Jewish mother (or those who underwent a halakhic conversion) are considered Jewish, then that makes him Jewish. His father is not Jewish.
Jake Gyllenhaal (whose full birth name is Jacob Benjamin Gyllenhaal) was born on December 19, 1980 in Los Angeles, California, U.S..
He is an Oscar-nominated actor known for his work in films like Donnie Darko (2001), Brokeback Mountain (2005, for which he was nominated for the Academy Award for Best Supporting Actor), Jarhead (2005), Zodiac (2007), Love and Other Drugs (2010), Source Code (2011), End of Watch (2012) and Prisoners (2013).
If you see any details that require update, please Let us know!