Josh Brolin

Brolin was born on February 12, 1968, in Santa Monica, California, the son of Jane Cameron (née Agee 1939–1995), a casting director and wildlife activist, and actor James Brolin. Brolin was raised on a ranch in the Adelaida area of Paso Robles, attending elementary and middle school in Templeton, California. Brolin moved to the Santa Barbara area around the age of 11, where he attended Santa Barbara High School. Brolin had little exposure to his father's acting career. His parents divorced in 1984 when Brolin was 16.

Brolin said in a 2014 interview that during his youth, Brolin was a member of a surfing friendship group who called themselves the "Cito Rats". In his description of the group, Brolin said, "It was Santa Barbara. It was the '80s. It was punk rock. You either had the children of rich, neglectful parents or children of poor, so it was a mix. But we basically grew up the same way. I've never seen a group like that before or since." He admitted to stealing cars to pay for his drug use, which included heroin, a drug that he explained he did not like: "I mean, I never got into it and I never died from it, which is a good thing. I've had 19 friends who died. Most of those guys I grew up with, they're all dead now." Brolin later said: "The group of guys that I grew up with, 37 of them are dead. 12 are in jail. 4 are in jail and also dead. I keep careful count, all 37 dead guys. I'm from a tough environment, ya know?"