The perfectly titled Joan Jett documentary, Bad Reputation, opens with a story the former Joan Larkin tells about her desire as a 13-year-old for a Sears electric guitar. (Adding to the vibe, she tells it in the grittiest, most punk-rock voice imaginable.)

Her parents didn't understand why she would want such a thing, but they got her one. She wailed away on it until she became as good as—if not better than—the teen boys also dreaming of rock-and-roll stardom in the SoCal suburbs of the 1970s. In Floria Sigismondi's 2010 feature film The Runaways, Jett (nicely played by Kristen Stewart) pays for a guitar with handfuls of coins, but this story is more telling.

Jett got her start by hanging out at the Sunset Strip nightclub Rodney Bingenheimer's English Disco, where she plunged into the glam-rock scene. In retrospect, it's hard to believe they let in teenagers like 14-year-old Joan. As with Manhattan's Studio 54, every manner of vice was on offer, but she emerged relatively unscathed. Through the club, she met the notorious Kim Fowley (played by Michael Shannon in The Runaways), who helped her put together an all-girl band. As Iggy Pop quips, not inaccurately, "Kim Fowley looked like Frankenstein if Frankenstein was on crack."

If Jett longed to be taken seriously as a musician, the overwhelmingly male-dominated media of the time couldn't see past the Runaways' jailbait image (manager Fowley, who used it as a marketing tool, shares in the blame). Only in London, during the punk era, did Jett feel like she fit in. It's no wonder that she would end up working with members of the Sex Pistols and the Germs. In the documentary, Debbie Harry of Blondie, Ian MacKaye of Fugazi, and Adam Horovitz of the Beastie Boys also pay their respects.

Director Kevin Kerslake (Nirvana: Live! Tonight! Sold Out!!) proceeds through the years as Jett struggles to remain commercially viable, a challenge for any legacy act, irrespective of genre, gender, or orientation. Then along came the riot grrrl movement, which brought Jett back to her punk roots. In addition to her production work for Bikini Kill, and cowriting credits with Kathleen Hanna, she joined forces with the surviving members of the Gits to promote women's self-defense and to search for Mia Zapata's killer (her voice breaks when she discusses the late Seattle singer). She has also played for the troops and spoken out on behalf of LGBTQ rights and the benefits of vegetarianism.

Jett has always been fiercely protective of her private life, but the clues are there in her lyrics, like her 1981 cover of Lesley Gore's proto-riot-grrrl classic "You Don't Own Me" ("Don't tell me what to do, don't tell me what to say") or her declaration on 1994's "Spinster": "I'm no one's wife, and I'm not your little girl." On "Fragile," from her most recent album, 2013's underappreciated Unvarnished, a 54-year-old Jett sings: "I'm at the point in life now, I think about my own mortality and how it all works out. I lived the best I could, but is that a bluff? I see myself and wonder, was that good enough?"

Is there any doubt? No one—not even Cesar Award–winning actress Kristen Stewart—is better at being Joan Jett than Joan Jett.