Paul Simon Faced Unexpected Struggles. Cameras Were Rolling.

Paul Simon had only one request of the filmmaker undertaking “In Restless Dreams,” a documentary about his life: “He wanted the music to sound good,” the director and producer Alex Gibney said.

Over the years, Gibney, 70, has told the stories of many lives, including Elizabeth Holmes’s (“The Inventor: Out for Blood in Silicon Valley”), Lance Armstrong’s (“The Armstrong Lie”) and Dilawar’s, an Afghan farmer who was tortured to death by U.S. soldiers in 2002 (“Taxi to the Dark Side,” for which he won an Academy Award for best documentary feature). He’s taken on musical legends like James Brown, Janis Joplin and Frank Sinatra.

The Simon film, however, came with the most tempting of offers: a chance to come out to the singer’s ranch in Wimberley, Texas, and film him as he worked on his latest album, “Seven Psalms,” which was released last year.

“That sort of thing doesn’t happen often at all,” Gibney said. “I got myself down to Texas as quickly as possible.”

“In Restless Dreams,” which premiered on Sunday on MGM+ (for TV viewers, the film is split in two, with the second half airing March 24), begins with Simon’s earliest days growing up in Queens, N.Y., as he and his onetime musical partner Art Garfunkel learned to harmonize by listening to the Everly Brothers. We see Simon (and sometimes Garfunkel) create beloved albums including “Sounds of Silence,” “Bridge Over Troubled Water” and “Graceland”; perform in Central Park in 1981, a concert that attracted half a million fans and led to a brief reunion of the duo; and tackle everything from movie soundtracks (“The Graduate”) to acting roles (“One-Trick Pony”).

There are several scenes of Simon working on some of American pop music’s most memorable tunes in a manner that has long impressed contemporaries like Wynton Marsalis, who met Simon in 2002. “He has a mystical understanding,” Marsalis said in a video interview. “He can see the timeless through the specific.”