Since the birth of alternative comedy, many standups have challenged authority, defended free speech and called for political change. But there have been few who fought as hard as Barry Crimmins.

On Thursday, Crimmins’s wife, Helen, announced that the 64-year-old comic had died of cancer. “He would want everyone to know that he cared deeply about mankind and wants you to carry on the good fight,” she wrote via her late husband’s Twitter account. And it’s true: Crimmins devoted much of his time and 40-year career to helping others and fighting injustices, both on and off stage. He showed integrity and compassion in all aspects of his life and work.

Crimmins started performing standup shortly after graduating high school in 1971. In the late 70s and early 80s, having moved to Boston, he was a central figure in establishing the city’s comedy scene. Not only through wielding his strong socio-political views on stage at a time when satirical standup was far from widespread, but by offering stage time to then newbies like Stephen Wright, Bobcat Goldthwait and Paula Poundstone at the two Crimmins-founded clubs, The Ding Ho and Stitches.

In comedy, Crimmins’s influence looms large over the current generation of satirists and east coast comedians. But although he inspired numerous big players on the scene today, the Kingston, New York-born comic always remained a cult figure, never reaching a level of fame that many of his successors did. “It wasn’t exactly profitable to be doing really harsh political [comedy],” said Patton Oswalt in the 2015 documentary about Crimmins, Call Me Lucky. “It was profitable to be doing fun political stuff … But he was almost heading into Noam Chomsky territory.”

On stage, Crimmins didn’t kowtow to standards or convention. He didn’t adapt and dampen his views to please an audience. He remained committed to his topics and opinions, and displayed an emotional core at the heart of his jokes. He was uncompromising in the best possible sense; he made no attempt to hide his righteous anger, and it made him a fascinating, insightful and unpredictable performer to watch.

Barry Crimmins in 2015. Photograph: Grant Lamos IV/Getty Images

But comedy is only one part of Crimmins’s mark on the planet. Outside of standup, he was an avid campaigner against child sex abuse, having been a survivor himself. In 1992, during a performance in Boston, he revealed that he had been raped when he was around four years old, and had suppressed the memories. He would later say, in an interview in 2005 with the Post-Standard, that he thought his comedy was a defense mechanism for dealing with his trauma.

Crimmins began to campaign on behalf of fellow victims and expose online paedophilia. Back when AOL went by the name “America Online”, the comic learnt that the website’s chat rooms were being used by predators to groom children. So, he spent hours posing as a 12-year-old boy called Sean to gather evidence and uncover the abusers.

When his complaints to AOL had no effect, he took his evidence to the FBI and eventually testified in front of Congress in 1995. Speaking of his testimony in an interview with Rolling Stone, Crimmins recalled watching footage of himself going head-to-head with AOL’s attorney. “You can see the weariness on his face because I didn’t give him a fucking inch all day,” he said. “It was like, ‘No way, motherfucker. This is for these kids. Fuck you, Jack. Fuck you and your fucking wind-tunnel haircut.’”

Just months later, the FBI made more than a dozen arrests, including three people that Crimmins had trailed. Eventually, AOL shut down chat rooms dedicated to child abuse content. “I thumped the massive corporation’s high-priced mouthpiece,” said a victorious Crimmins in a press release for a tour. ”[I] shamed them into a zero tolerance policy concerning the heinous crime of trading photographic evidence of children being exploited, sexually assaulted and/or raped.”

Crimmins’s story of surviving childhood abuse, and his subsequent activism against paedophilia – which he kept at until he died – became a prominent subject of Call Me Lucky. Fellow comedian Bobcat Goldthwait, who was directly inspired by Crimmins, directed the documentary, which premiered at the Sundance Film Festival in 2015 and won six awards at film festivals across the US.

Call Me Lucky has had a big impact among survivors of abuse, and brought further attention to Crimmins’s campaign. “I now hear from a lot of people,” he said in an interview with Time Out London in 2016, “and try to help as best I can.”

Following the film’s release, in what would be his final few years, Crimmins saw a resurgence of his career. In 2016 he toured the UK to critical acclaim, and later that year released a taped special.

Most recently, though, Crimmins had largely been devoted to caring for his wife, Helen, who is battling stage IV non-Hodgkins B-cell lymphoma. With huge healthcare costs – even with insurance – benefit gigs and crowdfunding campaigns were set up to raise money for her treatment. It was only a few months later that Barry himself was diagnosed with cancer, too.

As Helen tweeted, Crimmins fought the good fight, on behalf of himself and others, right up until his final few months. He helped shape the views of many through his tireless campaigning and uncompromising standup. And while he always remained a comedian first, Crimmins was proof a standup comic can provide more than just laughs.