The music and persona of Elvis Presley were potent influences on 20th century pop culture and that’s reason enough to be curious about his place in history. But I am particularly interested in comeback stories and the career span of a pop star. You can only be the face of youth culture for so long before changing tastes push you to the side. What then?

The music industry is unforgiving of these inevitable growing pains. Sometimes performers find a compelling middle ground between nostalgia act and fading away altogether. Most aren’t so lucky. Most don’t have the talent and charisma of Presley, either. Oh, what could have been.

The Paramount+ documentary “Reinventing Elvis: The ’68 Comeback” offers a hint as to how Presley might have navigated his career if things had panned out differently — namely, if he had extricated himself from his domineering manager Colonel Tom Parker, who was intent on keeping the money train rolling at the expense of anything resembling artistic fulfillment for his client.

“Don’t trust anyone over 30” was the youth mantra of the moment. And there was Presley, ancient by those standards at 33, trying to stake his claim with a return to television for the first time in a decade. Producer and director Steve Binder played a key role in shaping that 1968 NBC special and his wry and matter-of-fact recollections form the backbone of the documentary.

Binder had no problem ignoring the bulk of Parker’s staid ideas and that was just fine by Presley — finally, someone to stand up to the insufferable Parker. Even so, he was wary and told Binder he didn’t want to do television because it wasn’t his turf. That didn’t rattle the director: “I said, ‘Elvis, what’s your turf?’ And he said, ‘My turf is making records.’ And I said, ‘Great. You make a record, and I’ll put pictures to it.’ ”

And what pictures they were. Elvis in that form- fitting black leather suit, performing in-the-round to a small but enraptured audience. The footage is disarming because it’s so intimate and spontaneous-feeling. Inspired by the late-night jam seasons Presley would host in his dressing room after rehearsals, Binder decided to re-create some of that looseness and informality for the camera. The stripped-down aesthetics are an obvious precursor to “MTV Unplugged,” but they make up just one portion of a much longer (and more traditionally shot) TV special that was filmed on a soundstage with sets, costume changes and background dancers.

Presley stepped into the ’60s after a two-year stint in the Army that had been orchestrated by Parker as a way to reset the singer’s persona and make it more palatable for a broader (older) audience. But by the end of the decade, his career had devolved into a succession of mediocre films. The documentary spends too much time on the movies, while gliding past the music he released in these years, with “Are you Lonesome Tonight?,” “Surrender,” “It’s Now or Never,” “Can’t Help Falling in Love” and “Return to Sender” among them. It’s true that his musical output was mostly pegged to his movies, but he also recorded a couple of gospel albums during this period. In other words, he was down but not exactly out.

Even so, popular music had moved on without him. In 1968, the top five albums that year were from The Beatles, Simon & Garfunkel, Jimi Hendrix, The Rolling Stones and The Doors. Presley was out of fashion. But he was still enough of a name and a draw that NBC would build a TV special around him set to air just ahead of the Christmas holidays.

John Scheinfeld, who directs the Paramount+ documentary, has a long resume of projects that distill 20th century pop cultural figures down to their essence, including for Rosemary Clooney and Frank Sinatra. But by focusing on just a few months in Presley’s career, he has created a rich portrait of not only the singer, but the era itself.

When it came time to step on stage, Presley was nervous. This was palpable to everyone behind the scenes, but also obvious to the dancers (the one interviewed here played the leggy blond with whom Elvis nuzzles in the bordello sequence) as well as at least one audience member Scheinfeld was able to track down. That nervousness and his visible sweat has a way of humanizing Presley in some unexpectedly interesting ways, which makes it even more thrilling when his old confidence comes roaring back. But the title of Scheinfeld’s documentary is something of a misnomer. It wasn’t that Presley reinvented himself. But for a brief moment, he and Binder found a way for his talents to make sense and explode off the screen once again, even within the context of the psychedelic ’60s.

Not that it stuck. Presley remained in Parker’s bubble thereafter and the final years of his career — the Vegas years — live in modern memory as a novelty act. He still drew crowds. Big crowds. But he wasn’t able to build off the energy and promise of relevancy that he and Binder captured in that TV special.

In 1968, Presley was renting a home in Beverly Hills with his wife, Priscilla, and their newborn daughter, Lisa Marie. According to Binder, he told everyone didn’t want to battle traffic every day — that was the official story, anyway — so a bed was installed in his dressing room, and he lived at the studio. The documentary doesn’t dwell on this, but I couldn’t stop thinking about it. What a choice, to live across town from your wife and newborn baby. The couple had married only a year before and would divorced in 1973. Four years later, Elvis was dead at just 42.

How to watch: Paramount+