Following the financial and critical success of their London-to-Broadway productions of “War Horse” and “One Man, Two Guvnors,” executives at the National Theater of Great Britain announced on Thursday that they are opening their first office in New York next month to oversee future shows and deepen relationships with theaters and donors in the United States. While no new National shows are in the immediate offing for Broadway, the executives said, the new office is poised to make the National even more of a force in American theater than it already is.

The National has been a player on Broadway since 1967 when its first artistic director, Laurence Olivier, exported its production of “Rosencrantz and Guildenstern Are Dead” to New York; that black comedy by Tom Stoppard won the best play Tony Award and ran for a year. In the four decades that followed, the National mostly allowed Broadway producers to do the work re-mounting the London shows in New York.

But that changed with “War Horse” (which won the best play Tony in 2011) and “One Man, Two Guvnors,” which won the Tony for best actor in a play in June, as National executives took a hands-on role as a lead producer of the two plays. “War Horse” has become a major hit: Theater executives familiar with the Broadway production say it turned a profit several months ago and has become a solid money-maker for the National and its New York partners, Lincoln Center Theater and producer Bob Boyett. The play is set to close at Lincoln Center Theater on Jan. 6, 2013; a national tour is now underway. “One Man, Two Guvnors” closed on Broadway this month, meanwhile, after recouping its capitalization costs as well.

Nick Starr, executive director of the National, said in an interview on Thursday that he did not expect a wave of National productions to flood the New York marketplace, nor was the office a foothold for “a rampant growth strategy into America.” Rather, he said, the office will support the National’s new role as a lead producer across the country, as well as replace the arrangement that the National has had over the years with American producers like Mr. Boyett.

“If we produce something that seems to have wide appeal, we ourselves will take the lead in looking to move it – rather than have an American partner come over and assess it – and look into whether it’s a show that would fit well on Broadway or Off Broadway or at a nonprofit theater or somewhere else,” Mr. Starr said.

Mr. Boyett had been paying the National an undisclosed sum of money in exchange for a first-look deal until last year; going forward they will collaborate on producing National transfers on Broadway whenever Mr. Boyett chooses to participate, he and Mr. Starr said. In a separate interview, Mr. Boyett said he was “pulling back a little bit” from producing on Broadway, where he has been mounting or investing in a couple of shows a year; he emphasized that he was not retiring, but rather taking time to develop some long-term stage musicals (which he declined to discuss) and possibly produce a television series (work he did for decades).

“The National is ready and eager to move into lead producer status in New York,” Mr. Boyett said. “For myself, I want to be a little more selective in what I do and focus on major projects, whereas the National’s New York office can focus on doing shows with any partner it wants, like BAM or a nonprofit theater.”

The National’s profile in the United States has also grown through the spread of NT Live, its relatively new program of screening its stage productions at movie theaters. The latest screening has been the play adaptation of Mark Haddon’s popular novel “The Curious Incident of the Dog in the Night-time,” a critically acclaimed production that the National (which has three theaters in its South Bank complex) is now considering moving to another space in London for a longer run.

“It’s fair to say that once we have that cracked, we’ll probably turn our attention for ‘Curious Incident’ to North America,” Mr. Starr said.

The New York office of the National will open in early October and be run by Tim Levy, who has been working with Mr. Boyett and the National on productions in recent years, including “One Man” and “War Horse,” as well as being a producer on Punchdrunk’s “Sleep No More” show in New York.The office will have about five people, including a couple of fundraisers who have been assiduously courting new donors in North America.