Documentary filmmaker Davis Guggenheim may be best known for his political work directing award-winning films such as An Inconvenient Truth (2006) and Waiting for Superman (2010). His latest film, Still: A Michael J. Fox Movie, takes a narrower scope, following the Back to the Future actor’s life and struggles with Parkinson’s disease.

The subject may seem unexpected, but Mr. Guggenheim credits the Vineyard for the serendipitous turn of events. He has been coming to the Island since he was kid and his parents bought a home in Vineyard Haven in 1974.

About 10 years ago he was eating dinner at The Black Dog Tavern when Mr. Fox, a fellow summer resident, first approached him.

“It was kind of dark, you know, and I just see this figure approaching at kind of an odd speed and an awkward tilt,” Mr. Guggenheim said. “And he comes up to me and he asks, ‘What was Jimmy Page like?’”

Mr. Guggenheim said he didn’t recognize the star at first, but slowly realized it was Mr. Fox as he peppered him with questions about his 2008 rock documentary It Might Get Loud.

“A lot of us think of him as they remember him in movies,” Mr. Guggenheim said. “Unlike a lot of celebrities, he was very easy to talk to.”

The director planning a shot. — Courtesy Apple TV +

The pair would not cross paths again until several years later when Mr. Guggenheim, retreating to the Island at the beginning of the Covid-19 pandemic, stumbled upon an article about Mr. Fox and his Parkinson’s diagnosis.

Mr. Guggenheim had been struggling with depression at the time, he said, feeling out of step with his life and his family. He was struck by Mr. Fox’s frank, yet optimistic approach to his disease.

“He had this self-deprecating charm that I found appealing,” he said. “It struck me that a guy with this really terrible diagnosis was finding humor and joy in his situation.”

He called Mr. Fox’s agent and gave him the pitch: a documentary about the actor’s life, both public and private. Mr. Fox readily agreed, he said. The filmmaker’s next challenge was sifting through decades of television, film and interview footage, as well as several memoirs, to find the narrative within Mr. Fox’s life.

“Going into the movie, there were two expectations that I wanted to dispel,” Mr. Guggenheim said. “The first is that typical, oh, isn’t it so hard to be rich and famous?...The other one is, is this person with a disease or quote-unquote disability noble or pathetic?”

To avoid those so-called “traps,” Mr. Guggenheim worked with editor Michael Harte to imbue humor and vitality into Mr. Fox’s story. Originally, Mr. Guggenheim wanted to show Mr. Fox’s past entirely through staged reenactments, but Mr. Harte encouraged him to draw from the deep well of existing television and film footage.

The result is a speed run through Mr. Fox’s life, consistent with the actor's own hyperactive self-imagination. Through sit-com reels and red-carpet coverage, the audience watches as Mr. Fox goes from child actor to ubiquitous heartthrob, culminating in his Parkinson’s diagnosis in 1991.

Mr. Guggenheim also uses this approach when telling the story of how Mr. Fox met his wife, Tracy Pollan, another longtime seasonal Vineyard resident. Ms. Pollan had been cast as Mr. Fox’s love interest on Family Ties and their onscreen romance, continuing with Bright Lights Big City, paralleled their real-life courtship.

Davis Guggenheim on the set. — Courtesy Apple TV +

As Mr. Fox tells it in the movie, Ms. Pollan first impressed him when she called him an asshole at the height of his Back to the Future fame. “Nobody had ever spoken to me like that,” he says with a grin.

The documentary also shows glimpses of Mr. Fox’s life on the Vineyard, spending time with his children and practicing physical therapy. The Island’s presence is subtle until it comes out that he named his daughter “Aquinnah.”

Despite its difficult subject matter, the film retains the sense of humor that had first captured its director. Mr. Guggenheim said he grew to admire the role humor plays in Mr. Fox’s life.

“I had underestimated him in my casual assessment,” he said. “I think we have a prejudice against funny people...You don’t see a lot of comedies up for Best Picture...They’re seen as less serious, less intelligent.”

“In making this film, I learned there is a subtle and deep wisdom in comedy,” he continued.

The film, which premiered May 12 in theatres and on Apple TV+, owes much of its post-production to the Vineyard as well. Mr. Guggenheim and Mr. Hart spent long days editing footage on the Island, even hosting a few preliminary screenings at the Martha’s Vineyard Film Center.

“The breakthrough happened on Martha’s Vineyard,” he said.

After viewing an early cut of the documentary, Mr. Guggenheim’s daughter, Stella, suggested that he end the film with a lingering take of Mr. Fox looking directly at the camera.

“We screened it at the film center, and I was like, that works,” he said.

Mr. Guggenheim had final cut of the documentary, meaning he could make “whatever movie I wanted to make.” The film looks starkly at Mr. Fox’s admitted struggles with workaholism and alcoholism, but Mr. Guggenheim declines to offer up a moral takeaway.

“I don’t read self-help books,” he said. “I don’t like when people are preaching to me or telling me how to live my life, and Michael never does that.”

“That’s what makes him so interesting,” he continued. “He did a lot of the wrong stuff before he did the right stuff.”

He said that Mr. Fox loves the film and has been texting him excitedly with every positive review. The warm reception comes as a relief for Mr. Guggenheim, but he added that the process of making the film had already benefited him tremendously.

“Three years later, I’m much more hopeful, much more upbeat, much more grateful in the everyday moments of my life.” he said. “That’s what I got out of making the movie, and I hope people in watching the movie get a contact high from that.”

When Mr. Guggenheim returns to the Island this summer, he said he will be focused more on relaxing than on finding inspiration for his next project.

“I’ll do a lot of reading...and hope that something lands at my feet,” he said.

Still: A Michael J. Fox Movie is currently screening online and at the Martha's Vineyard Film Center. Remaining shows at the film center are May 24 at 7:30 p.m. and June 1 at 4 p.m.