As artistic director of the Hull House Theatre, located in the Jane Addams Center, in the 1960s, he helped give Chicago something it had never had before: an indigenous theatre culture. He nurtured talents who would become defining figures in the city's theatre, such as playwright David Mamet, Jim Jacobs, the author of Grease, and actor Mike Nussbaum.

His productions of plays by Samuel Beckett, Harold Pinter, Bertolt Brecht, Jack Gelber, Edward Albee, Arthur Kopit and others were hailed almost from the start. Sometimes designing the sets and lighting as well, he creating productions on a shoestring that appeared to theatregoers and critics to be quite fully formed. Of Frank Gilroy's Who Will Save the Plowboy?—the production that opened his Hull House reign—critic Richard Christiansen (who who become the dead of Chicago theatre reviewers) wrote "This is the most important achievement for theatre in Chicago since a group of young actors took over an old Chinese laundry and turned it into a cabaret called Second City!"

At a time when regional theatre was still dominated by touring productions that emanated from New York on one end, and community theatre on the other, Mr. Sickinger opened the city's eyes to the talent that in its own backyard. Reviewers routinely remarked on his ability to draw professional-caliber performances from amateurs.

William Robert Sickinger was the son of Frank P. Sickinger, owner of the Motor Freight Company, and the former Mary Raimondo, and was raised in Philadelphia. According to his own account, he one day walked past a movie theatre in his neighborhood that was being converted into a skating ring. "Without a penny in my pocket I talked the owner into renting this 400-seat theatre for $200 a month," he recounted. From 1952 to 1955, he staged productions there of Our Town, All My Sons, Country Girl, Come Back Little Sheba and others. In 1955, he began mounting works at the more centrally located Circle in the City. Further Sickinger presentations were at the Cricket Playhouse, Abbey Playhouse and the Philadelphia Civic Theatre.

In 1963, he moved to Chicago, lured to the Hull House by its new executive director, Paul Jans, who wished to rejuvenate the organization's theatre program. There, he began to focus more on challenging dramas, the sort that didn't make it to Broadway. At the time, Mr. Sickinger regarded Chicago as a "theatrical desert." "I believe in the grass-roots theatre," he said. "You can't build an interest in the theatre in a city by importing shows. You've got to grow them from within."

Mr. Sickinger's moment in the sun lasted about five years. He suffered a setback when Jans, his steadfast supporter, resigned. Soon after, the Hull House's board, which hadn't always been happy with the director's choice of plays, or his sometimes abrasive personality, announced Mr. Sickinger's departure. (That the theatre, which the Hull House had always financed, had never been able to make money didn't help.)

Though the Chicago theatre community he helped engender went on to prosper, Mr. Sickinger did not play a role in the growing movement. He left Chicago in 1969, divorced his wife, Selma, and moved to New York, where he eventually ran an answering service.

"I tried to direct theatre and film when I came to New York," he told the Chicago Reader in 1999, "but I found it very difficult. I probably moved the wrong way—I should have gone to California. But I don't miss it, really. I had true love once, in Chicago. That was pretty much a perfect experience. And when you've had true love, nothing else is as good."