When New York gallery legend Ivan Karp refers to the Los Angeles art scene of the 1950s as a “miasmal mist in the distance,” he’s not kidding. Isolated in a city that couldn’t have cared less about them, the artists who forged a tight creative community in Los Angeles — including Billy Al Bengston, Ed Kienholz, Larry Bell, Kenneth Price, and Ed Moses — were practically nonexistent.

As Mr. Bengston notes in Morgan Neville’s new documentary, “The Cool School,” which opens Friday at Cinema Village, the assortment of abstract modernists, many of whom took up cheap residences above the derelict streets of Venice Beach, were as few in number as the young men taking up the nascent sport of surfing.

It took the persistence and savvy of a young gallerist named Walter Hopps to catalyze the scene through his Ferus Gallery, which opened on La Cienega Boulevard in 1957 and gradually dispersed the miasma, creating a buzz out of a vacuum. “He was a CIA-FBI sort of guy,” Mr. Bengston says, recalling the black suit, skinny tie, and wide-frame glasses the late Hopps favored in his youth.

The detached air was in sharp contrast to the larger-than-life personae adopted by his artists, macho characters who scavenged scrapyards (Kienholz) and transposed custom hot rod fetishism to the art studio (Mr. Bengston), and whiled away their after-hours at a bar called Barney’s Beanery.(“You had to bring your own girl,” one of the artists laments. “It was pretty sparse as far as women went.”)

Mr. Neville’s documentary, which was co-written and produced by the longtime Los Angeles-based journalist Kristine McKenna, is a poignant and affectionate capsule history of a movement. The film’s direct chronology and straightforward narration (by Jeff Bridges) isn’t as deliberately arty as its subjects, but it’s also looser and more fun than a Ken Burns exhumation would be. Expert witnesses (including the painter and Newsweek art critic Peter Plagens), survivors (Mr. Bengston), second-wave inheritors (Ed Ruscha), celebrity enthusiasts (Dennis Hopper, Dean Stockwell), and various ex-wives weigh in with testimonies, and generous stock footage does the rest.

The scene really only began to explode after Kienholz, who had partnered with Hopps in the gallery, left to devote his full attention to his infamous assemblages. Hopps, who died in 2005, found a new partner in Irving Blum, a flamboyant, Pop art-loving dealer whom everyone likened to Cary Grant. Mr. Blum’s taste for showmanship and ease with the moneyed classes were the polar opposite of Hopps’s ascetic manner, and together they made a perfect odd couple. Suddenly, work that seemed to be pure and iconoclastic assumed collectible value, and a movement was born.

The film waxes rather elegiac toward the end, as the remaining principals of the Ferus era reunite for the first time since the late 1960s, some obviously holding up better than others. There’s a photo session and a flashback to the same artists as burly, shirtless bohemians. As Kienholz’s widow remembers, the artist insisted that the next generation should happily “push me into my grave.”

Turns out, he meant that literally. After he died, Kienholz was entombed inside one of the custom cars (in this case, a 1940 Packard coupe) he loved, with a dollar and a deck of cards in his pocket, a bottle of Chianti beside him, and the ashes of his dog, Smash, in the trunk. When the car wouldn’t start properly, it had to be shoved forward into the gaping grave by his young mourners. Such a perfect coda.