Levine was born in Los Angeles, the son of Patsy Noah and Fred Levine. His uncle is Slate writer and editor Timothy Noah. He has a brother, Michael, and a sister, Julia Milne. When he was six, he made the winning shot of his local YMCA championship basketball game (on a team his father coached) with no time left on the clock. He has said that the incident changed his life and gave him the confidence to be successful.

Levine attended French Woods Festival of the Performing Arts Camp (Hancock, NY) with best friend Jesse Carmichael, guitar player of the band known at that time as Kara’s Flowers. He graduated from Brentwood School in 1997.

Levine has Jewish ancestry on both sides of his family (his father and maternal grandfather were Jewish), and considers himself Jewish, though according to The Jewish Chronicle, who interviewed Levine, he “has rejected formal religious practice for a more generalised, spiritual way of life”. As a child, when asked by his father whether he wanted a bar mitzvah, Levine said no.