McFly: The surname of the time-traveler Michael J. Fox played in “Back to the Future” suits that character, by design. It also captures the propulsive stardom and perpetual motion of the actor who became a star, then a superstar, and then a struggling, secretive superstar dealing with a degenerative brain disease.

The Edmonton, Alberta, native was diagnosed with Parkinson’s in 1991, when he 29. Fox kept it under wraps for much of the 1990s. Masking his tremors as cleverly as possible, he soldiered through his second major sitcom, “Spin City,” the one following the star-making ‘80s phenomenon “Family Ties.” He went public in 1998 and has become a conspicuous fundraising force for Parkinson’s research.

In Chicago, the annual Doc10 nonfiction film festival opened Thursday with “Still: A Michael J. Fox Movie,” with director Davis Guggenheim (”An Inconvenient Truth,” “He Named Me Malala”) in attendance at Lincoln Square’s Davis Theater. Fox, who turns 62 next month, is living a life of supreme paradox. It took Parkinson’s, he says at one point, to slow down and realize the heartbeat of his days, day by day, step by step. Success? That he dashed through on the way to something else. Guggenheim’s film chronicles that something else.

The best parts of “Still” simply show us what Fox’s days entail. We see him working with a physical therapist/trainer on exercises and strategies to avoid another fall. In close-ups of Fox, the retired actor regards Guggenheim’s camera in various states of tamped-down physical pain and unwanted motion. Periodically, especially after a dose of dopamine, those symptoms calm down. Before Parkinson’s, he tells the off-camera Guggenheim, “I was never still.”

For Fox, typically the smallest boy in his classes, the early years growing up in Edmonton meant darting away from much larger and meaner boys, or parrying potential threats with a wisecrack. He was funny and made the most of it. It led Fox to try Hollywood (after a Canadian sitcom “Leo and Me”) as a high school dropout. He struggled for three long, lean years, winning a few small parts, losing out on many more, including Timothy Hutton’s role in “Ordinary People.” (He recalls that director Robert Redford “spent the audition flossing his teeth.”)

“Family Ties,” on which Fox took off as Reagan-era paragon Alex Keaton, changed everything, while refocusing creator Gary David Goldberg’s show away from the parents and directly onto Fox (and, secondarily, Justine Bateman). All this, leading into “Back to the Future” and beyond, makes for a classic star-is-born triumph, though even prior to his Parkinson’s diagnosis, the obstacles and evasions loomed. Fox’s marriage to his “Family Ties” co-star Tracy Pollan — they’ve been married for 34 years — endured many long distances (Fox never wasn’t working, often a long way from Los Angeles), and Pollan’s near-solo parenting of four kids. Meantime, Fox’s alcoholism and “hide-the-bottle” coping mechanisms helped him “dissociate” (his word) from his own worsening condition.

Now 30 years sober, Fox’s resolve, his ever-sharp wit and acuity, more than mitigates what’s not entirely useful in Guggenheim’s filmmaking approach. The documentary goes in for a lot of flash and dazzle: elaborately slick and percussively edited dramatic re-creations of his earlier years; constant and often obvious use of Fox’s TV and film appearances to comment on a crisis or a turning point; an intrusive musical score; it can get to be more competition than context for its subject.

These are objections regarding the how, and how much, of a specific type of documentary technique. Most folks, I suspect, will not mind the way “Still” handles things. It’s entertaining. And its best, it backs off and lets Fox’s presence, the grace-filled and inspiring way he has risen to an extremely tough occasion, reflect the man’s lives and times.

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'STILL: A MICHAEL J. FOX MOVIE'

3 stars (out of 4)

Rated: R (for language)

Running time: 1:35

How to watch: On Apple TV+ stasrting today