New Orleans-based photographer Curtis Knapp’s portfolio is a veritable constellation of famous faces.

It’s an A-to-Z list that includes dozens of boldfaced names from the past four decades, from baseball legend Hank Aaron to trailblazing musician Jon Zorn — with an impressive cast of personalities from the worlds of film, music, sports, art and fashion in between, many of whom Knapp captured early in their careers.

There’s a young Madonna, her face starkly lit and framed by her hands in a style deliberately reminiscent of a classic portrait of Greta Garbo. There’s a young Michael Stipe from R.E.M., looking every bit the alternative teen pop idol with a curly mop of hair. And there’s a young Branford Marsalis, captured with a cocky grin during a tour of Japan as he was achieving new heights of international fame.

Not a bad lineup for a guy from Long Island, New York, who would later wind up running a gallery in New Orleans almost by accident, with stints in New York and Tokyo as an art director and advertising photographer for clients like Apple, Levi’s, Nikon and Playboy along the way.

Knapp began taking pictures in the late 1970s after studying commercial illustration at New York’s Parsons School of Design. Friends brought him down to Athens, Georgia, at the moment when bands like R.E.M. and the B-52s were beginning to explode on the national pop consciousness, and his photographs of the Athens bands helped propel what was to become a career as a sought-after celebrity portraitist.

“I’m still friends with a lot of the people I photographed in those days,” said Knapp.

Indeed, a sense of familiarity between artist and subject has informed much of Knapp’s portraiture ever since.

A series of photographs of Andy Warhol shows the artist eating sushi and working on a large canvas with a marked lack of self-consciousness — no mean feat for a subject who was always aware of how he was being represented. Other subjects like actor Steve Buscemi and poet John Giorno look less like they’re posing for a public relations opportunity than individuals who just happened to stop by Knapp’s studio for a visit. (Which, in the case of a luminous portrait of singer and actress Michelle Phillips, wasn’t far from the truth: “That photo was taken in my dining room,” said Knapp.)

Knapp continued to make portraits after moving to New Orleans sight unseen in 2007. “For some reason, it just appealed to me,” he said. Local stars like Amanda Shaw and Deacon John are now part of his portfolio.

And while the strong formal qualities of his photographs show Knapp’s self-proclaimed debt to influences such as Irving Penn, the intimate and comfortable expressions of his subjects is a testament to the down-to-earth nature of Knapp himself.

“I’ve been described as a goofball,” he said. “But I guess that’s helped make people feel comfortable with me when I’m taking their portrait.”

It’s an attitude that has served Knapp well in his current incarnation in his gallery on Decatur Street just off Frenchmen in the Faubourg Marigny, which he opened as a solo venture in late 2014 after curating several shows for its former owners.

Along with the Scott Edwards Gallery on the same block, Knapp’s space has become a central part of the small but growing art district which lies about halfway between the more established Julia Street and St. Claude scenes in location and sensibility.

The gallery serves not only as an exhibition space for Knapp’s own photographs (which have been published in several books as well as in a custom-designed iPad app) but also for work by several emerging and established local artists.

And Knapp also intends the Decatur Street location to be another venue for his portrait services, at prices which he describes as in keeping with the neighborhood aspect of his gallery.

“There’s some really great artists in this town whose work I want to show,” he said. “And my door is always open to anyone who wants my kind of portrait for themselves.”