'Only Murders' fans: Steve Martin's full life on display in Apple TV+ doc 'Steve!'

For younger Americans, Steve Martin is that white-haired guy who plays pompous amateur sleuth Charles-Haden Savage in Hulu’s hit show, “Only Murders in the Building.”

What a joke. And a shame.

Fortunately, director Morgan Neville (“Won’t You Be My Neighbor?”) is here to remind us of Martin’s outrageously varied 50-year career with “Steve! (martin) a documentary in 2 pieces,” a nearly four-hour Apple TV+ film that delves into the keen mind and often lonely heart of a bona fide genius.

Not that Martin, 78, would agree. “I guarantee you I have no talent,” he says in the doc. “If I’d had guidance, I’d have gotten nowhere.”

But by forging his own path, Martin redefined comedy before embarking on a career as an author, playwright, movie and TV actor – and, lest we forget, a highly accomplished bluegrass banjo player.

Introspection isn’t Martin’s thing, but he warmed to Neville. “At first Steve said he wasn’t going to watch the doc,” Neville says in an interview. “Then he did, and I got a text that said, ‘Loved it. Can I show it to my shrink?’”

More revelations from “Steve!” about an American original:

Audiobook highlights:'The Steve-ness of it all': Steve Martin talks tour with Martin Short, new audiobook

Steve Martin’s drive to succeed came partly from a search for parental approval

Martin grew up in southern California and discovered his love of performing as a teenage magician working at Disneyland. But his father, Glenn, a real estate salesman and aspiring actor, was perpetually hard to win over.

Even during Martin’s late-1970s heyday, his father’s comment after one sold-out performance was, “Here’s what was wrong with that show.”

Decades later, father and son reconnected. As Glenn lay dying, Martin wrote in a moving New Yorker story in 2007, his father turned and said: “You did everything I wanted to do.”

A girlfriend helped steer Steve Martin to his off-kilter brand of comedy

Martin idolized legends such as Jack Benny but knew a punchline-driven approach would not work for him. Then a girlfriend suggested he read, “The Razor’s Edge,” a 1944 W. Somerset Maugham novel about a spiritual quest.

Martin had two revelations: one, he would try a more philosophical approach to comedy, and two, he would “give this my all until age 30, and then become a professor of philosophy.”

Martin worked tirelessly in the early ‘70s until finally, his persona as a “comedian who thinks he’s funny but really isn’t” caught on with counterculture crowds. The dam broke in 1975. He had just turned 30.

Steve Martin arguably was the Taylor Swift of comedy in the late ‘70s, and then it ended

Between 1975 and 1980, Martin became a cultural phenomenon. His comedy records such as "A Wild and Crazy Guy” sold in the millions, and he went from playing small clubs to massive arenas.

Much like today's adoring Swifties, Martin fans showed up with his trademark arrow-through-the-head garb and spouted his catchphrase, “Well, excuuuse me!” His hosting appearances on NBC's "Saturday Night Live" became must-see TV. But by 1980, Martin realized it wouldn't last.

Says Neville: “Steve’s standup career was really performance art. So when the audiences got the joke, it was over. The moment he felt he was cresting, he decided, ‘I’m done.’ Which is a theme with him."

Steve Martin had many movie successes but was often crushed when they didn’t resonate with audiences

Over roughly 40 years, Martin has made dozens of films, including successes such as “The Jerk,” “Dirty Rotten Scoundrels,” “Father of the Bride” and “L.A. Story.” In many instances, he also co-wrote the screenplays.

But “Steve!” reveals that Martin was crushed when some films struck out, including the musical “Pennies From Heaven,” for which he learned to tap dance, and “Leap of Faith,” a film about a preacher that Martin was sure would bring him acting accolades.

His obsession with success sabotaged relationships. He married his “L.A. Story” co-star Victoria Tennant in 1986, but they split without having children. “He was very, very shy,” Monty Python alum and friend Eric Idle says in the documentary. Director Frank Oz calls Martin “closed off.” Martin dove into his passion for art to stay sane.

“I told Steve, we don’t need to see Mary, but I want people to see you as a father,” says Neville. But Martin being Martin, he can’t resist a joke. When she enters the room and embraces him, Martin quips, “Remind me your name?” When she leaves, he pats his heart.

A dream eventually led Steve Martin to embrace parenthood and a new standup life

“Steve had a dream around 1998, in which a person told him his life needed adventure,” says Neville. “But the person didn’t mean travel; she meant people. And now, years later, Steve is not such a lonely guy. He has a family, he has Marty (Martin Short), he has a (bluegrass) band. He’s surrounded by people.”

In 2007, Martin married Anne Stringfield, 51, his fact-checker at The New Yorker. In 2012, the couple welcomed daughter Mary. At Martin's request, Mary is seen only as a stick-figure drawing in “Steve!"

Steve Martin’s friend Martin Short helps keep his anxieties at bay

A constant presence in “Steve!” is Short, 74, who first teamed up with Martin in “The Three Amigos” (1986), again in “Father of the Bride” (1991) and is now part of a traveling standup act with Martin as well as a co-star in “Only Murders.”

In “Steve!,” the friends are seen workshopping their act, driving around Los Angeles landmarks and biking around Santa Barbara. “Steve still has anxiety (about performing), and Marty has none,” says Neville. “As soon as Marty enters the room, Steve relaxes."

Adds Neville: “In many ways, Marty actually is the wild and crazy guy Steve pretended to be, so in a way, being with Marty is like being with his former self."