Steven Dietz is one of the most successful playwrights in the country. Why?

It seems a churlish question, for several reasons. First, because he’s an authentic Seattle success story, coming here in 1988 at the request of Jeff Steitzer at ACT, who premiered his breakout hit God’s Country, a docudrama about Northwest white supremacists. What’s more, even though he moved to Austin in 2006 for a teaching gig, he returns each summer with his family, even as his national profile continues to rise. He’s also a famously nice guy, particularly in the theater community. Actors invariably love working with him (he also directs), fellow playwrights marvel at his generosity and support of their work, and directors find him artistically open and a tireless rewriter. He’s even an inspiring teacher, as I learned after taking a class from him this past summer. All this certainly makes it easy to understand why regional theaters line up to produce his plays—particularly when he’s written so many for them to choose from.

Because if there’s one quality that sets Dietz apart from many of his contemporaries, it’s that he’s bewilderingly prolific, having had more than 30 full-length plays and adaptations produced in the past 25 years. Becky’s New Car, his new play previewing at ACT this week, is his ninth at ACT and one of three premiering this year. Though he’s never had a New York hit, his plays have been translated into seven languages and have become staples of regional and fringe theaters across the country.

“I’m having revivals!” he laughs. “That’s when you know that you’re a 50-year-old playwright!”

Becky’s New Car, a comedy about a middle-aged woman with a drab but serviceable existence who suddenly gets the chance to “road test” another life with a millionaire, was written on commission, like almost all of his work these days. “Kurt [Beattie, the director] told me that he wanted an ensemble comedy, and I said, ‘Oh, sure.’ Even though the hardest thing to write is a good ensemble comedy.” He describes the show as “a fast-moving comedy without any doors,” with a serious message about the midlife desire to change direction, and he’s pleased to have added yet another theatrical genre to his long list.

Yet while his profligacy and hard work have provided a thick catalog of plays for theater producers, it hasn’t necessarily helped him with the critics. If anything, they seem bewildered by his hopping about amid a whole series of theatrical genres, from Stoppard-like domestic comedies (Private Lies, Fiction) to literary adaptations (Dracula, Sherlock Holmes: the Final Adventure) to children’s plays (Still Life With Iris, Honus and Me). His dramas often ride onto the scene at the same time as a whole clutch of similar plays by other authors, like autobiographical immigrant stories (Handing Down the Names) and even AIDS dramas (Lonely Planet, probably the nearest thing he’s had to a “breakout” play). Like a reliable supporting actor, his work is omnipresent but strangely indistinct. It’s hard to say just what a Dietz play is, and even harder to know if there’s a truly great play that he’s yet to write, or just a steady stream of pretty good ones. (And if he does eventually pen his masterpiece, will it be recognized as such before the next play comes along?)

What his scripts almost always feature is deft structure and storytelling, so much so that plot may be the backbone of his talent. Even his least successful plays feel brick-solid while you’re watching them—though afterward they slide out of the mind like oyster shooters, with hardly any aftertaste. Dietz admits that his attention to plotting occasionally kills some of his artistic spontaneity. “I’ve got plays sketched out in my notebooks where the director and the structuralist in me has laid them out so firmly that I’ve diminished my interest in writing them. What I tell my students is that you have to be careful to remember the play’s initial impulse, and make sure a little madness can always creep in.”

He admits the scripts that are his personal favorites, like Inventing van Gogh, are often the ones for which there was a significant lag between conception and creation (12 years, in Vincent‘s case). When I ask him if there are any plays he’d like to “take back,” I gamble he won’t be offended, and he isn’t. “I’m sure that some people would like me to take some of them back, but no,” he says, then mentions Walter Kerr’s famous quip: “Neil Simon didn’t have an idea for a new play this year, but he wrote it anyway.”

“I remember hearing that when I was a young man and thinking how clever that was. But the longer I write plays, the more I side with Simon on that quip. Because this is what I do! You climb really hard up to a place where you can get your plays done, and now that I’m here, and people are doing my work, of course I’ll keep writing. It’s the job.”