Cannibalism rarely serves as a good career move. But it has sustained Issei Sagawa, now 69, since the 1980s. Books, movie roles, a comic book, countless talk-show appearances in his native Japan — even a verse in the Rolling Stones song “Too Much Blood” (“And when he ate her he took her bones/To the Bois de Boulogne”) — all stem from a horrendous act he committed in 1981.

While pursuing a Ph.D in comparative literature at the Sorbonne in Paris, Sagawa lured classmate Renée Hartevelt to his apartment under the premise that he needed help learning German. Hartevelt turned her back; Sagawa produced a gun and prepared to shoot the Dutch woman from behind. But he lost his nerve and could not pull the trigger.

Unfortunately, she paid him a second visit. This time, he shot her.

“He killed her and raped her and started eating her,” said Verena Paravel, co-director of the documentary “Caniba,” playing at Museum of the Moving Image through next Sunday. “But he had issues with the [raw] flesh and cooked her. He made a teriyaki.”

As the remains began to smell, Sagawa decided to dispose of Hartevelt. He put her dismembered corpse into two suitcases and brought them to a large park outside Paris. “How he did it was so stupid,” Paravel told The Post. “He did it before sunset, when there were many people in the park.” Sagawa was spotted trying to dump the blood-dripping suitcases in a lake, and authorities were summoned. “I think he wanted to be caught,” Paravel added.

Upon capture, Sagawa confessed: “I killed her to eat her flesh.”

French psychiatrists deemed that Sagawa — who would later tell Vice that he’d been fascinated with cannibalism since staring at a classmate’s thigh in the first grade — to be “completely crazy and irresponsible.” (He also allegedly had intended to dine on a sleeping German woman in 1970 in Tokyo, but fled when she awoke.)

After his arrest, he was committed to a psychiatric hospital and kept there until 1983, when the French shipped him back to Japan.

The cannibal ended up translating his fame to soft-core porn films in which he would bite his co-stars, and even a job as a ­sushi critic.

Incredibly, he was not tried in his homeland. Although it’s unclear why, one theory suggests that the Japanese could not obtain key prosecutorial documents from France.

Though well-educated, Sagawa was largely unemployable after the killing in Paris. “But he loved media attention,” said Lucien Castaing-Taylor, the movie’s co-director. The cannibal ended up translating his fame to soft-core porn films in which he would bite his co-stars, as well as on the lecture circuit and even a job as a ­sushi critic. “He . . . went on talk shows to [dryly] discuss what he did,” Castaing-Taylor added. “In his media representations, he didn’t [acknowledge doing] anything wrong. We saw no expressions of remorse.”

By the time the filmmakers caught up with Sagawa in 2015, he was suffering from diabetes and had suffered two heart attacks.

Shunned by most of his family, Sagawa now lives quietly outside Tokyo. He is confined to a wheelchair, reliant on public assistance and looked after by his brother Jun — who displays his own peculiar fetish in the movie: wrapping his arms in barbed wire and digging at the wounds with sharp tools.

To make the film, the directors spent several months with the brothers, often staring at Sagawa and exchanging no words while forming a bond of trust. This approach paid off when Sagawa walked the filmmakers through the panels of his illustrated confessional, a highly graphic mangacomic book. Written and illustrated by Sagawa, it is currently out of print and available on Amazon for $248. The graphics depict him committing his heinous act and exposes the insecurities that led him there.

Standing less than 5 feet tall and with tiny hands, Sagawa, who never married, believed that he was too ­repulsive for physical intimacies that may have sated his desires.

Self-loathing is explicit in the ­illustrations. “I don’t think there is anything as obscene as him reenacting and recounting what he had done,” said Castaing-Taylor.

Brother Jun agreed. “He got angry at us after the manga [was discussed with the documentary cameras rolling],” recalled Paravel. “He said, ‘It’s going to ruin my brother’s reputation.’ I thought that was completely hilarious. It is my ­favorite line in the movie.”

That said, for all the shock value in “Caniba,” the directors aimed to convey something old-fashioned. “I think it is a brotherly-love story — but fraught with hatred and profound competition,” said Castaing-Taylor. “At some point Jun asks, ‘As your brother, would you eat me?’ ” The only response is prolonged silence.

Like much of Sagawa’s life, Castaing-Taylor added, the moment “is frightening and comic and very disturbing.”