Blake Robison, who became producing artistic director of Bethesda’s Round House Theatre in 2005 and has spearheaded a repertory built on literary adaptations for the stage, announced Thursday that he is leaving the company to head Cincinnati’s Playhouse in the Park.

Robison’s departure, effective at the end of Round House’s 2011-12 season in June, creates a rare opening in a leadership job at a theater of substantial size in the Washington region. In its 34th season, the company, which operates a 400-seat main stage in Bethesda and a smaller black-box space in Silver Spring, draws the majority of its audience from Montgomery County and Northwest Washington.

“It’s been an absolute joy,” Robison said by telephone from Cincinnati, where his appointment was to be revealed at a news conference Thursday. “I love Round House. Professionally, I’ve done my best work so far here. Some lucky person is going to inherit it.”

Sally J. Patterson, president of Round House’s board of trustees, said a search committee has been formed in hopes of securing a successor by mid-spring.

“He is one of those rare artistic directors who thinks with both the left side and the right side of his brain, the artistic as well as the finances,” she said. “And he has been a really great face of the organization in the community.”

In Cincinnati, Robison, 45, will oversee the principal nonprofit theater company, an institution that produces 11 plays and musicals each year. (Its 2006 revival of Stephen Sondheim’s “Company” transferred to Broadway.) With 850 seats in two theaters and an annual budget of $10 million, the Playhouse in the Park is about double the size of Round House, which offers a main-stage season of six productions on a budget of $5 million.

“It’s an exciting opportunity for me, personally,” said Robison, who was hired away from the Clarence Brown Theatre in Knoxville, Tenn., when Round House tapped him to succeed longtime producing artistic director Jerry B. Whiddon. “I didn’t go looking for it; I was contacted over the summer to see if I wished my name to go forward. I’ve always said the only thing that would pull me away would be an opportunity to work at a flagship theater.”

In a theater market as competitive as Washington’s, there is a tendency for a mid-size company such as Round House to be overshadowed by the bigger city players, such as Arena Stage, Studio Theatre and Shakespeare Theatre Company. Robison attempted to cement a distinctive role for Round House by refining the company’s mission around seasons of works for the stage inspired by or based on literature. This approach gave Robison, a stage director himself, more programming leeway than one might imagine; the offerings at Robison’s Round House have ranged from adaptations of novels such as “A Prayer for Owen Meany” to regional premieres of musicals such as “Summer of ’42.”

He has thrown some world premieres into the mix, and although the formula has kept the company on solid ground — “We’re in good shape, we have no debt,” Patterson said — the quality of the work has gone up and down. For every very fine adaptation, such as Robison’s excellent “The Talented Mr. Ripley” in 2010, there has been a corresponding failure, such as the 2009 unveiling of a garish version of “The Picture of Dorian Gray.”

Still, Robison was the steward of Round House’s successful foray into Silver Spring with the black-box space next to the AFI Silver Theatre. The company has opened up the location to smaller troupes, such as the critically lauded Forum Theatre. Patterson said the Silver Spring space is fully booked and “is an asset on our books.”

“Blake has been a great mentor,” said Michael Dove, artistic director of Forum, which recently completed a well-received run of Caryl Churchill’s “Mad Forest.” “He really got to know our work. He really came to see everything. He’s been such a great champion for us.”

Robison said he wishes he could have produced even more new work at Round House, but the recession and the costs of developing original work made that ever more difficult. But he said he is deeply proud of the company’s output, as represented in productions such as “Ripley,” in that “it had a visual aesthetic that we had been working toward.”

He’ll be in Bethesda throughout this season, with one eye looking west, to Ohio. He does, after all, have to begin to figure out how he’ll be filling those spaces next year in Cincinnati.