The cause had not been determined, but Mr. Reems had been in declining health for some years, his wife, Jeanne, said.

The arc of Mr. Reems’s life — which took him from Marine to “Deep Throat” to mendicant to successful real estate broker — came to renewed attention in 2005 with the release of “Inside Deep Throat,” a documentary about the film’s legacy for which he was interviewed on camera.

The scheduled release this July of “Lovelace,” a biographical film starring Amanda Seyfried as Linda Lovelace and Adam Brody as Mr. Reems, seems likely to ensure his continued place in public memory.

Mr. Reems, who began his career in the 1960s as a struggling stage actor, had already made dozens of pornographic films when he starred opposite Ms. Lovelace in “Deep Throat.”

But where his previous movies were mostly the obscure, short, grainy, plotless stag films known as loops, “Deep Throat,” which had set design, occasional costumes, dialogue punctuated by borscht-belt humor and an actual plot of sorts, was Cinema.

Mr. Reems played Dr. Young, a physician whose diagnostic brilliance — he locates the rare anatomical quirk that makes Ms. Lovelace’s character vastly prefer oral sex to intercourse — is matched by his capacity for tireless ministration.

“I was always the doctor,” he told New York magazine in 2005, “because I was the one that had an acting background. I would say: ‘You’re having trouble with oral sex? Well, here’s how to do it.’ Cut to a 20-minute oral-sex scene.”

“Deep Throat” quickly became an international sensation: the subject of debates, pro and con, concerning its redeeming social value, and of self-congratulatory cocktail-party chat among the intelligentsia.

It was responsible for turning Mr. Reems, with his immense black mustache and shirts, opened to the navel to reveal an almost preternaturally hirsute chest, into a one-man avatar of the ’70s.

It was also responsible for his conviction on federal conspiracy charges and, he said afterward, his descent into alcoholism, destitution and homelessness before finding faith, a happy marriage and bourgeois respectability.

Mr. Reems was born Herbert Streicher in Brooklyn on Aug. 27, 1947, into a Jewish family. (His nom du cinéma was bestowed by the director of “Deep Throat,” Gerard Damiano.) Young Herbert passed his adolescence, by his own later account, as “a shy kid with a lot of pimples and a big nose.”

After high school he enlisted in the Marine Corps, where he cultivated the strong, sinewy body that would become his calling card. In the late 1960s, after his father died, he obtained a discharge and moved to the East Village.

He acted in Off Off Broadway plays, but, needing money, took work in pornographic films. Among them were “Mondo Porno,” “The Altar of Lust” and “Erecter Sex” Parts 3 and 4.

Mr. Reems’s Schwab’s drugstore moment came after Mr. Damiano hired him to be the lighting director on “Deep Throat.” When the original male lead failed to show up for work, Mr. Reems stepped in.

For the film, which was widely reported to have grossed more than $600 million, Mr. Reems was paid about $250.

However, as he told it, there were other compensations: parties at the Playboy Mansion, hobnobbing with celebrities and fending off (or not) throngs of adoring women.

Then, one day in 1974 Mr. Reems was arrested in New York by federal agents. The next year he and 11 others, many of them organized-crime figures, were tried in federal court in Memphis on charges of conspiracy to transport obscene material across state lines. (“Deep Throat” was widely reported to have been financed by associates of the Colombo crime family.)

It was during the trial, Mr. Reems said, that he began drinking heavily.

After he and his co-defendants were found guilty in 1976 Mr. Reems became a First Amendment cause célèbre, with a string of Hollywood celebrities speaking out on his behalf.

“Today, Harry Reems; tomorrow, Helen Hayes,” Warren Beatty was reported to have declared.

Represented on appeal by Alan M. Dershowitz, Mr. Reems had his conviction set aside by a federal judge in 1977.

Mr. Reems, who made more than 100 films, went on to star in “The Devil in Miss Jones” (1973) and “Memories Within Miss Aggie” (1974), both directed by Mr. Damiano, as well as “Pleasure Cruise” (1974) and “For Your Thighs Only” (1984).

But pornography is a young man’s game, and by the mid-1980s demand for Mr. Reems had abated. By then he was adrift, drinking, by his count, two-and-a-half gallons of vodka a day.

He fetched up in Los Angeles, begging on the streets and sleeping in Dumpsters. He contemplated suicide, he said, but could not summon the nerve.

In 1989 Mr. Reems, then living in Park City, Utah, stopped drinking with the help of a 12-step program. He converted to Christianity, obtained his real estate license and married Jeanne Sterret in 1990.

Besides his wife, Mr. Reems’s survivors include a brother, Robert.

Ms. Lovelace died in 2002, at 53, of injuries sustained in a car accident; Mr. Damiano died, at 80, in 2008.

For the most part Mr. Reems led a life of contented small-town obscurity in Midway, Utah, golfing, attending church and collecting Brooklyn Dodgers memorabilia. He retained the name Harry Reems, he said in interviews, as a proud emblem of an odyssey he did not regret.

There was, Mr. Reems told The Ottawa Citizen in 2005, one lingering affinity between his early career and his later one as the owner of a successful real estate brokerage.

“I’m still selling dirt,” he said.