Describing an interview with Gary Busey is nearly impossible. On one hand, the experience is exactly what you might think: Frenetic. Unfocused. The works. His sentences are sprinkled with what he calls “Buseyisms”: acronyms he’s spelled out for decades that hint at his philosophy on life. B.I.B.L.E., for example, is “Basic Instructions Before Leaving Earth,” and partially the title of his memoir.

On the other hand, Mr. Busey, 75, still manages to surprise you. He came by The New York Times recently to discuss “Only Human,” a new Off Broadway musical in which Mr. Busey plays the role of God. The show, which begins previews Tuesday and opens Oct. 21 at Theater at St. Clements in Manhattan, is a contemporary workplace comedy featuring a showdown between Jesus and Lucifer, who battle over their new creation: Earth.

While this may seem like an odd fit, Mr. Busey said he hasn’t been as excited about a part since his Oscar-nominated title role in 1978’s “The Buddy Holly Story.” And why not? He has been a musician for decades, and counts several A-list musicians as friends, including Bonnie Raitt.

But Mr. Busey, who studied drama at Oklahoma State University, fell into acting and became a mainstay in television and film. Substance abuse and a serious motorcycle accident in 1988 derailed his life and career.