This January at the Sundance Film Festival, about a month before the documentarian Alex Gibney won his first Academy Award, he sat down to discuss his most recent work, a film about the late gonzo journalist Hunter S. Thompson. Here was a man, Mr. Gibney said, who mocked the entrenched voices of authority and challenged people to see beyond the status quo through his freewheeling indictments of a complacent society. While many of those closest to the maverick were not entirely surprised by Thompson’s 2005 suicide, Mr. Gibney said he still found several who were angry about the timing of the act. Given the way Thompson had rallied against the wars and politicians of the 1960s and ’70s, they said, his contrarian voice was sought now more than ever.

At Sundance, it only took a few days for word to circulate that “Gonzo: The Life and Work of Dr. Hunter S. Thompson” was a powerful and passionate profile of the famed writer and anarchist. But it wasn’t until a few weeks later that interest among the general public started to escalate, as Mr. Gibney’s “Taxi to the Dark Side” took home the Academy Award for Best Documentary. With “Gonzo” finally opening on movie screens across the nation next Friday, audiences will have the chance to check out Mr. Gibney’s portrait of Thompson, a biography far less interested in his insane personal life and recreational drug use than his inspired bouts of political activism.

“It actually speaks of him from within his era, showing the way he fought in his own time to take on the social system, the political system, and the world in general,” the artist Ralph Steadman, Thompson’s longtime collaborator, said. “It also gets that manic balance just right, showing how Hunter could go right to the edge, would push to the edge in hopes of shocking people, and then pull back at just the last second.”

Mr. Steadman, who discussed the film via phone from his London flat, is himself a central character in the film, as “Gonzo” chronicles the collaboration between Thompson and his mild-mannered English illustrator. Thanks in large part to his partnership with Thompson, the 72-year-old artist is regarded as an icon of animation in his own right. Today, Mr. Steadman’s severely angled, colorfully embellished illustrations, which provided seamless visual accompaniment to Thompson’s lyrical tales of drugs, madness, anguish, and exhilaration, cannot be viewed apart from their association with the words they adorned.

“The first time we ever met was at the Kentucky Derby,” Mr. Steadman said. Thompson was there to write what would become his legendary essay “The Kentucky Derby Is Decadent and Depraved,” which is dramatized in “Gonzo” and is as much about Thompson’s meeting with Mr. Steadman as it is about the race. “From our first meeting, he would goad me relentlessly. I think I was just too odd for him to leave alone, and that’s what attracted him — this English illustrator geek who would accompany him. He would poke fun at the fact that here we were, this Southern gentleman and this man with Welsh roots. He would say, ‘We Americans were civilized before you ever learned to take a bath.'”

While “Gonzo” jumps freely between decades, bringing to life not only Thompson’s run for mayor of Aspen, Colo., but also the frustration and depression that crippled him in his later years, it focuses chiefly on the period of 1965-75 when, as “Gonzo” suggests, Thompson was at the top of his game.

Utilizing Johnny Depp as narrator (who would have guessed?), the film quotes directly from the journalist’s texts, surveying his immersive coverage of the Hell’s Angels, his infuriated writing about the Kentucky Derby, and his outright attack on the modern American lifestyle via “Fear and Loathing in Las Vegas.” But these separate strands seem trivial when contrasted with Thompson’s fierce push into political journalism during the 1972 presidential election.

“How low do you have to stoop in this country to be president?” Thompson marvels via archival footage, just as Mr. Gibney re-creates the writer’s most brazen attempt to mock and debunk the political process by claiming that Senator Edmund Muskie was hallucinating on the campaign trail thanks to a drug called ibogaine.

“He was a cruel S.O.B. at times, but, man, was he funny,” Mr. Steadman recalled. “How’s this: I remember he had this bird, Edward, and he used to go and bang the cage. ‘Edward,’ he’d say, ‘I’m coming for you, I’m coming, Edward, and I’m going to destroy you.’ And then the bird would squawk and tear at his flesh as he put his hand in the cage; he would put up a hell of a struggle. And Hunter would just laugh. He was always doing stuff like that.”

Thompson’s need to agitate and provoke became addictive for Mr. Steadman. Recalling his days with the journalist, pausing regularly to laugh at the memories, the illustrator said he used to drop everything to work with him, and that more than once he enjoyed the thrill of feeling as if he might not come back alive from a Hunter Thompson assignment. There was the time Thompson sprayed him with mace in the middle of a restaurant, and the time Thompson handed him a can of spray paint and told him they were going to draw degrading messages about the pope.

“I think he wanted to find new ways of shocking me,” Mr. Steadman said, crediting their friendship in large part to something as simple as the sound and resonance of his first name. “I think it was because Hunter could bark at me, and it would just have that full sound — ‘Ralph!’ If my name was Kevin or Arnold, who knows.”

But Mr. Steadman connects with one of the central claims of “Gonzo,” that it was this odd pairing — the American and the Englishman, the scalawag and the quiet yet profound artist — that led to some of Thompson’s most inspired and influential work. “Faulkner said that real life is better than fiction,” he said. “The writer must be able to capture things as he’s going and get it down then and there. So he wouldn’t have notes, and then I would draw these pictures, which brought this whole new perspective, and he would be sitting there at the end of the week after being totally plastered and drunk, and he’d react to what I drew with that electricity of his.”

ssnyder@nysun.com