Albert Innaurato, 70, a Temple University grad whose dramas of self-realization found success on Broadway in the 1970s, was found dead Tuesday in his Philadelphia apartment. A cause of death had not been determined.

During his career, Mr. Innaurato earned two Obies, a Guggenheim Fellowship, and grants from the Rockefeller Foundation and the National Endowment for the Arts. His biggest hit was Gemini, set in mid-1970s South Philadelphia. For its time a frank and prescient coming-of-age and coming-out story, it had one of the longest runs for a Broadway play and has been revived several times, as both a stage play and a musical.

Born in 1947 in Philadelphia, Mr. Innaurato attended Central High School and Temple University. Eventually, he went to the Yale University School of Drama, where he befriended the playwright Christopher Durang (Vanya and Sonia and Masha and Spike). Durang, now in Bucks County, spoke by phone of their friendship: "We were in the same class, 1971, and we both had nuns in our plays a lot. Albert's were Italian and mine were from Ireland. For a while, we wondered whether there was room for both of us. But we made each other laugh and became good friends." Among their other good friends were Sigourney Weaver and the playwright Wendy Wasserstein.

Durang and Mr. Innaurato collaborated several times while at Yale, particularly on The Idiots Karamazov, a crazy deconstruction of Dostoevsky's novel featuring translator Constance Garnet in a wheelchair. "Albert played that part when the female lead broke her leg," Durang said. Later, in subsequent productions, the part was played by classmate Meryl Streep.

Mr. Innaurato enjoyed his greatest success in the 1970s, when his 1976 play Gemini, about Francis Geminiani, a young man who returns to his South Philly neighborhood, ran on Broadway for more than four years. "When he did Gemini first, it really was a game-changer, an extraordinary assertion of gay rights," said Marjorie Samoff, who worked with Mr. Innaurato at the Prince Music Theater. "To write in the mid-1970s about the difficulties of a gay kid in a macho family – it was a courageous endeavor."

Mark Brokaw, who directed a 1998 revival of Gemini in New York, said: "There were not that many plays at the time speaking of gay life in such a life-affirming way. It kind of led the way on that." Gemini was made into a film; a musical version played at the Prince Music Theater in 2004. Mr. Innaurato moved back to Philadelphia from New York to work on it with Charles Gilbert, then of the University of the Arts.

Another notable success was The Transfiguration of Benno Blimpie, a shattering play that begins with the lines "I am Benno. I am eating myself to death." The play won an Obie and was revived in 1983, under the direction of the author. It also was performed at the then-Philadelphia Company in 1978.

Durang remembered Mr. Innaurato as "remarkably funny, but also with an undertone of melancholy." Alexander Fraser, artistic director of the Bucks County Playhouse, said, "He could hold the room with his elaborate, always hilarious stories." Brokaw called Mr. Innaurato "wonderful to have in the room, warm, generous, knowledgeable." And Samoff called him "incredibly brilliant, especially on literature or music."

Mr. Innaurato wrote for television, including work for PBS and for The Days and Nights of Mollie Dodd. An accomplished musician, he was also deeply involved in opera, becoming a well-known writer and critic in the field. At what was then the Center City Opera Theater in Philadelphia, he was for a time artistic director of creative development projects, a workshop and development program for new operas. He was dramaturg and directed workshops of works including Paul's Case by Gregory Spears and Slaying the Dragon by Michael Ching. He helped develop The Great Blondin by Ronald Vigue, for which he was librettist. He also directed Philadelphia performances of classic opera for the company, including Eugene Onegin and The Magic Flute.

Mr. Innaurato had no immediate relatives, and no details of memorial services were available at the time of this writing.