Jim Mitchell, who died Thursday at his ranch in Petaluma, Calif. at 63, together with his brother Art Mitchell built a pornography empire that released some of the first feature-length skin flicks, in the 1970s. Years later, as the brothers lives devolved from drug-addled celluloid orgies to mere squalid violence, Jim Mitchell was convicted of killing Art Mitchell.

In the 1960s and ‘70s, the brothers produced a string of adult film hits, including “Resurrection of Eve” (1973) and “Sodom and Gomorrah: The Last 7 Days” (1975).

But their most famous and financially successful film was “Behind the Green Door” which starred Marilyn Chambers, who previously had worked as a model in Ivory Soap ads. That movie, which cost about $60,000 to make, reportedly earned $25 million. Appearing in 1972, the same year that saw the release of the even more successful “Deep Throat,” the film helped signal a new era of cinematographic permissiveness.

From their offices atop the O’Farrell Theatre in San Francisco, a combination movie-and-stage show emporium that opened in 1969 and was called the “Carnegie Hall of Sex,” the brothers built an empire that at one time included 11 movie theaters as well as movie and video production.

Using skills Jim Mitchell learned in film studies classes at San Francisco State University, the brothers began producing stag films starring old classmates from high school and hippies come to the West Coast to experience the “Summer of Love.” They worked their way up from 16-mm shorts to full-length features.

“So busy are the makers of porn films in San Francisco,” wrote Time magazine in 1970, “that they have depressed the market for imported sex movies, and are now selling their own products abroad — a small victory for the nation’s trade balance.”

Their success brought sustained recognition from the police, who raided their theaters on morals charges. At the height of their career they spent thousands annually on legal expenses.

Despite purveying material of unsurpassed graphic explicitness, the brothers had a knack for appearing more naughty than nasty. They raised funds to save the whales and the rain forests, and once demanded that TV host Geraldo Rivera donate $15,000 to AIDS-related charities before allowing him to film a strip show for television.

They also attracted a variety of friends, including Black Panther leader Huey P. Newton, cartoonist Robert Crumb, and Hunter S. Thompson, who worked for them briefly as night manager of the O’Farrell.

When Dianne Feinstein (now a California senator) of the San Francisco Board of Supervisors and later the city’s mayor tried to shut them down, the brothers displayed her private phone number on the O’Farrell marquee with the message: “For a Good Time, Call.”

The brothers’ personal lives were as complicated and expensive as their business dealings. Though joined at the hip professionally, each was married and divorced multiple times and each fathered numerous children. Jim was relatively quiet, while Artie was known as the party guy. But at 45, Artie was caught in a spiral of drug and alcohol abuse that prosecutors later said led to increasingly erratic behavior and disrupted the business.

Their empire came crashing down on February 27, 1991, when Jim Mitchell, armed with a pistol and a rifle, went to his brother’s home and shot him to death.

Prosecutors said the killing was a cold-blooded act sparked by a dispute between the brothers over the future of the business.

Jim claimed that the shooting was an accident that happened when he was trying to persuade Artie to seek treatment for drug and alcohol addiction.

Convicted of voluntary manslaughter, Jim was sentenced to six years at San Quentin State Prison but served less than three years. Several of his brother’s children filed wrongful death suits against him that eventually were settled out of court.

A film based on their lives, “Rated X,” appeared on Showtime in 2000. Directed by Emilio Estevez, it starred Estevez as Jim and his own brother, Charlie Sheen, as Artie.

After his release in 1997 from prison, Jim lived quietly, raising horses at his Petaluma ranch until his death.