Ginger Baker, former drummer for legendary British rock band Cream, is the subject of the doc “Beware of Mr. Baker.”

Put Jay Bulger in a box and he’ll punch his way out of it — literally. In his 30 years, the D.C. native has been a Golden Gloves boxer, a Vogue cover model, a cancer survivor and a Rolling Stone writer. That last one started as a bluff: He had to persuade Ginger Baker, the cantankerous drummer for legendary British rock band Cream, to talk to him so he could eventually direct a film about the elusive musician’s life.

Bulger was drawn to Baker as a fan of his music, but also because the drummer’s behavior had become the stuff of legend in recent years. (Four years ago, for instance, Baker offered to drop trou in court to prove his innocence in a financial fraud case.) In 2008, Bulger followed Baker to South Africa, moving into his secluded home there for two months. Baker didn’t turn out to be the easiest subject. Though he remains a respected artist, he’s also an ill-tempered scoundrel who suffers no fools — including Bulger.

Nevertheless, Bulger came away with his first article for a major magazine, “The Devil and Ginger Baker,” which ran in Rolling Stone in August 2009. The seven-page spread laid the groundwork for what would become Bulger’s first feature-length film, “Beware of Mr. Baker,” which he filmed during a follow-up trip in 2010. The brutally honest and rollicking documentary debuted at this year’s South by Southwest film festival and won the event’s jury award.

Ahead of the film’s screening Saturday at this year’s AFI-Discovery Channel’s Silverdocs festival, Bulger spoke about finding the humanity in such an irascible character.

What was the most difficult part of making “Beware of Mr. Baker”?

Ginger. He was really challenging. Sustaining that daily abuse was pretty hard without giving up. There was definitely a part of me egotistically wishing every day he’d be like, “Thank you so much for coming back, Jay! This is going to be such a good movie!”

What did he actually say?

“The movie’s [expletive] and you’re a [expletive] idiot!” So, that was hard. But you know, it’s funny … My entire life I have been delusionally confident, and I think I really appreciated [Baker] calling me out on my own bull[expletive] on a daily basis. It made me really take it seriously and work hard.

What do you hope people come away with when they see this film?

A deep understanding for someone who could easily have been misunderstood. I hope they come away understanding who Ginger Baker is on a very personal level, deep-to-the-core humanity.

Round House Theatre’s Forum Theatre, 8641 Colesville Road, Silver Spring; Sat., 1:15 p.m., $13; 301-495-6700. (Silver Spring)