The morning after the midterms, Chase Oliver was back at work. “That’s what most other Georgians have to do after an election,” he tells the Guardian. “I have a job and have to pay rent and the bills.”

Oliver, 37, has two jobs, actually – one as a sales account executive for a financial services company and another as an HR rep for a securities firm. And as he toggled between email replies and Zoom interviews from his north-east Atlanta home, with three cats and a dog, Delilah, underfoot, you’d never suspect this natty, young Georgian had thrown a spanner into the cogs of American power. “You are possibly the most hated man in America right now,” read one post to his Facebook page.

Oliver was the third candidate in Georgia’s US Senate race: a pro-gun, anti-cop, pro-choice Libertarian who proudly announces himself as the state’s first LGBTQ+ candidate – “armed and gay”, he boasts. And on Tuesday night, this surprise spoiler scored an historic upset of sorts, siphoning enough support away from the Democratic incumbent Raphael Warnock and his Republican challenger Herschel Walker to force the election to a 6 December runoff – Georgia’s second in as many election cycles. Until then, there’s no telling whether the Democrats will retain control of the Senate.

Exactly who went for Oliver remains disputed: he reckons his typical voter was a left-leaning independent who might otherwise have voted for Warnock. But one pollster predicted Oliver’s success was more likely about pulling away “soft Republican” votes from rightwing voters who couldn’t face voting for Walker.

Even more impressive than the 81,000 votes Oliver tallied on election night was the $7,790 he raised campaigning to win them. Of the record $8.9bn spent nationally on federal campaigns this election cycle, Georgia Senate candidates raised $136m, one of the most expensive contests in the country.

Oliver’s was a true grassroots campaign. He hosted a watch party for the only Walker-Warnock debate and walked in Pride parades waving a rainbow-colored Don’t Tread On Me flag now perched outside his garage. On the front lawn are campaign signs for his fellow Georgia Libertarian challengers. When I compliment his modern ranch-style home from the comfort of a screened-in back porch, he’s quick to note that he pays rent to a live-in owner and mostly keeps to the basement – campaign HQ, officially. Inside, more Oliver lawn signs and posters share wall space with portraits of members of Star Trek’s Starfleet.

Despite his obvious need, Oliver refused to indulge into the usual groveling for campaign cash. “I’m not someone who likes to get on the phone and beg people for money,” says Oliver, who instead relied on the kindness of friends, family and fellow Libertarians. The bulk of that fundraising went toward yard signs, canvassing materials and gas for his beat-up Toyota Corolla. “It’s not the prettiest in the world,” he says of the car – which, among other things, is missing a cover for the rear bumper. “But it gets great mileage.”

On election night, Oliver watched from home with friends, picking over chicken wings when he wasn’t exchanging texts with his campaign team. Beforehand, he had been polling at about 5%; anything above 2% figured to spark a runoff, given how close the race was between Warnock and Walker already. When Oliver settled just above 2% and stayed there and neither frontrunner retained more than a 50% + 1 vote share, the minimum standard for victory, Oliver celebrated the coming runoff – which he says he caused partly to prove the need for ranked-choice voting across the country. “That’s the real lesson I want people to learn,” he says. “Whether you voted for Raphael Warnock or Herschel Walker or me, we wouldn’t have to wait weeks later to see who’s going to Washington DC if we passed something common sense like ranked-choice voting.”

Oliver makes no effort to hide his healthy contempt for the current two-party system. But he wasn’t always so disillusioned. As an out teenager in a state where laws against sodomy were aggressively enforced until the state supreme court invalidated them in 2003, Oliver launched his high school’s gay-straight alliance. Oliver remembers screening Brokeback Mountain when it opened in 2005 and being so moved that he dragged his straight friends to the theater to see it the very next week. He thought, “This is what’s gonna get all my friends to understand the struggle,” he says. “But they did not have the same experience. They were like, ‘It was a good movie, but you kinda oversold it.’”

He gravitated toward the Democratic party because of Barack Obama, inspired by promises to bring home the troops, close Guantánamo and draw down the US’s drone-strike program. But as Obama betrayed those promises, Oliver decamped for the Libertarians – a 50-year-old party that’s more culturally liberal than Democrats and fiscally conservative than Republicans and the third-largest political party by voter registration. Oliver’s platform runs from immigration reform to world peace. But it’s government dysfunction that really animates him. “There’s no real legislating going on,” he says. “What we’re seeing now is leadership drafting a bill behind closed doors with giant corporate interests.

“It doesn’t matter who wins, Raphael Warnock or Herschel Walker; they’re going to be a cog in that system.”

Oliver struggled for face time alongside the Senate frontrunners. When Walker flashed a fake police badge during his debate against Warnock last month, Oliver joined the meme parade, promising to bring his Starfleet pin to a subsequent debate against Warnock. (“Apparently, badges are required for debates now,” he tweeted.) But when Oliver pushed the senator on the Democrats’ flawed criminal justice policies, Warnock mostly ignored him.

Although Oliver has received some threats, he tells friends not to worry about security. (“I conceal carry, so I’ll be taking care of myself as always,” he says.) To those who might bemoan this nerdy young white guy in the first Georgia Senate race to feature two Black candidates, Oliver invites would-be critics to check his record. “People who know me know that I’ve always worked with a diverse coalition of activists to get things done,” he says. “I think no matter what the skin color of the Republican or Democratic candidates, they would have been somebody I had severe policy disagreements with.”

Still, many Georgians are likely to resent Oliver anyway for further drawing out what’s seemed like an endless campaign cycle – not least the exasperated voters who supported Oliver. While Oliver sympathizes with voter frustrations (and is exhausted with the campaign crush himself), if at the very least it brings about the end of runoff elections, history might say it was worth it. “I wanted to be an honest broker,” Oliver says. “I’m hoping that whoever wins this runoff reaches across the aisle a bit more and actually does some real legislating.”

• This article was amended on 11 November 2022. An earlier version misstated Raphael Warnock’s record on LGBTQ+ rights.