Despite his success, the serious-minded Gibson — whose plays often dealt with historical characters and eras — was not altogether pleased with the experience. He was pressured to make numerous changes to the script to satisfy the box-office-minded producer and the star, Henry Fonda, who had grown dissatisfied with his part. He found solace by keeping a diary. The following year, he published a memoir, "The Seesaw Log," related his alarm and ambivalence to the events that surrounded him becoming a successful playwright. In one section, during the Philadelphia tryout, he wrote that he suffered the "paradoxical experience of seeing his work improve by becoming poorer."
Mr. Gibson's second Broadway effort landed him a permanent place in regional and community theatre for the next half-century. Inspired by the ordeal educator Annie Sullivan underwent in trying to teach the dumb, deaf and blind Helen Keller how to learn, he wrote an 1880s-set teleplay called "The Miracle Worker" for Playhouse 90. The writer drew partly on Keller's "The Story of My Life" and partly on a printed volume of Sullivan's letters.
It was nominated for an Emmy. He then adapted it into a stage play. Seesaw star Bancroft was cast as Sullivan, and young Patty Duke was chosen to play Keller, in a star-making role. Penn again directed. The play proved a critical and popular hit, and Penn, Bancroft and Gibson all won Tony Awards. (Bancroft's becoming a star was largely due to her work in Gibson plays.) It was subsequently made into a 1962 film with the same cast. Mr. Gibson wrote the screenplay and was nominated for an Oscar.
"It was obviously a love-letter," Mr. Gibson said of his play. "I like to fall a little in love with my heroines, and the title — from Mark Twain, who said, 'Helen is a miracle, and Miss Sullivan is the miracle-worker' — was meant to show where my affections lay. This stubborn girl of 20, who six years earlier could not write her name, and in one month salvaged Helen's soul, and lived thereafter in its shadow, seemed to me to deserve a star bow."
Mr. Gibson was brought in by Penn to complete Clifford Odets' book to the musical Golden Boy when Odets died in 1963. The musical—starring Sammy Davis, Jr., as a young man forced into the quick commercial world of boxing to escape his dead-end circumstances — debuted in 1964. He was again nominated for a Tony.
The playwright never again scaled the dizzying career peak he reached in the late 1950s. A Cry of Players, which was set in 16th-century England and conjectured about Shakespeare's origins, flopped in 1967. The Penn-directed The Monday After the Miracle, a sort of sequel to The Miracle Worker starring Jane Alexander and Karen Allen, ran seven performances in 1982. And the musical Raggedy Ann, for which he wrote the book, played five shows in 1986.
He had an unexpected late-career hit with an Off-Broadway production of his solo Golda Meir play Golda's Balcony, a revision of an earlier play about the Israeli prime minister. It starred Tovah Feldshuh, transferred to Broadway in 2003 and ran for a year-and-a-half.
Jonah's Dream, a new work, debuted at Connecticut Repertory Theatre in 2005, the same year the writer was inducted into the Theater Hall of Fame.
Also a novelist, his book "The Cobweb," set in a psychiatric clinic, was adapted into a 1955 movie directed by Vincente Minnelli. He published a collection of verse, "Winter Crook," in 1948.
William Gibson was born in the Bronx in 1914 into a Catholic family. His father was a mailroom clerk in a bank — a prosaic fate Mr. Gibson was determined to avoid. Early on, he was attracted to writing, and studied creative writing at City College, later dropping out. His first paid piece was a short story published in Esquire for $150 during the 1930s. Over the following years, Mr. Gibson roamed around, trying any number of activities. He acted in Abingdon, VA; becoming an organizer in the Young Communist League; and played piano in Topeka, KS, where he met his wife, Margaret Brenman-Gibson.
After his agent suggested he try plays, he began writing scripts for the Topeka Civic Theatre in Kansas. When Two for the Seesaw was produced on Broadway, he sold the script to Hollywood for $600,000, allowing him a measure of comfort and the chance to move to the Berkshires. (A musical version of the play, called Seesaw, and directed by Michael Bennett, had a year-long run on Broadway in 1973.)
Mr. Gibson married Margaret Brenman-Gibson, who was an eminent psychotherapist and biographer of Odets, in 1940. Her influence, many critics said, could be found in her husband's plays, which often puzzled over the way the human mind works. She died in 2004.
Survivors include two sons, Thomas Gibson of Stockbridge, MA, and Daniel Gibson of Cambridge, MA.
