This theater image released by the O+M Company shows Lauren Culpepper, left, and Zosia Mamet, in a scene from MCC Theater’s production of "Really Really", performing off-Broadway at the Lucille Lortel Theatre in New York. (Janna Giacoppo/AP)

— From the outset, the box-office appeal of “Really Really” astonished actor-turned-playwright Paul Downs Colaizzo. He was surprised when Eric Schaeffer, Signature Theatre’s artistic director, green-lighted his play, about irretrievably self-absorbed and entitled college students, for a world-premiere run in Arlington County, and startled again when it became the most successful nonmusical the company has ever produced.

“It was a delightful start, the reception in D.C.,” Colaizzo said recently, over lunch at Bond 45, a restaurant just off Times Square. “But in New York, I didn’t want to take that as acceptance.”

He needn’t have worried. In a new production directed by David Cromer and featuring Zosia Mamet — daughter of playwright David and star of the hit HBO series “Girls” — “Really Really” has repeated its D.C. success. MCC Theater, the off-Broadway company that produced it here, has extended it twice, with a closing now set for Saturday. Over its run, a steady stream of theater notables has filled the seats of the sold-out Lucille Lortel Theatre; at a matinee a few weeks ago, actors Kevin Bacon and Kyra Sedgwick and playwright Neil Labute were among the appreciative throng that packed the place.

The previously unheralded Colaizzo has been served well by “Really Really” — and so, by extension, has Washington theater. A positive reception in the outside world is not the be-all or end-all for a D.C.-bred play; in fact, some actors and others who have focused their careers on District stages shrug scornfully at the notion of out-of-town validation. Yet there is added psychic capital to be tallied, and pride of place to be recognized, in a city that can regularly export its theatrical wares to other cosmopolitan centers.

Washington, of course, has been making plays that the world takes for almost as long as there has been a regional theater movement in this country: Back in the 1960s, Arena Stage famously minted the original production of Howard Sackler’s “The Great White Hope,” which did wonders for the careers of a couple of young actors named James Earl Jones and Jane Alexander. Still, too few plays have moved on of late quite as visibly and deftly as “Really Really” to declare categorically that Washington’s star is again ascendant on the national stage. On the evidence, though, of “Really Really” and other D.C.-honed plays and musicals receiving productions in New York City and elsewhere, it is clear that the footprint of Washington’s nonprofit theater world is getting bigger.

Four shows that got a start or a grooming in Washington have landed on Broadway this season, and two were D.C. world premieres: Craig Wright’s “Grace,” the existential thriller starring Paul Rudd and Michael Shannon, was unveiled by Woolly Mammoth Theatre in the fall of 2004, and “Scandalous,” a musical about evangelist Aimee Semple McPherson by Kathie Lee Gifford, made its debut at Signature in 2007 as “Saving Aimee.” The Steppenwolf Theatre revival of “Who’s Afraid of Virginia Woolf?” that closed this month at the Booth Theatre was featured at Arena Stage two seasons ago. And “Ann,” Holland Taylor’s solo show about the late Texas governor Ann Richards, had a crucial booking late in 2011 at the Kennedy Center.

The critical and popular receptions for these productions have ranged from ecstatic (“Virginia Woolf”) to kind (“Grace”) to dismal (“Scandalous,” which shuttered after only three weeks at the Neil Simon Theatre).

Other works birthed in Washington have achieved noteworthy results on a variety of dramatic platforms. “Giant,” for instance, Michael John LaChiusa’s musical based on the sprawling Edna Ferber novel of the same title, debuted at Signature in 2009, inaugurating the company’s American Musical Voices Project. This fall, the show, slimmed down from its original four-hour running time, attracted admiring notices at off-Broadway’s Public Theater. And last month, at Chicago’s American Theatre Company, “Columbinus,” a drama about the 1999 shootings at Columbine High School first performed at Round House Theatre in 2005, was enthusiastically endorsed by critics there.

Because many Washington theaters are deepening their investment in new plays — Duncan Macmillan’s “Lungs,” for example, has been staged in Philadelphia, the Berkshires and Britain since its premiere at Studio Theatre in 2011 — the opportunities for expansions of Washington’s cultural reach are growing, too. Playwrights Horizons, in New York, has announced that its 2013-14 season will begin with Anne Washburn’s brilliant “Mr. Burns, a Post-Electric Play,” which Woolly Mammoth premiered a year ago. Even the Capital Fringe Festival is proving to be fertile turf: “The Brontes,” a raucous rock satire by Fringe favorite Dizzy Miss Lizzie’s Roadside Revue, is in talks to perform this summer at a festival of new musicals in New York.

For playwrights such as the 27-year-old Colaizzo, a Georgia native and NYU grad who began focusing on a writing career only about four years ago, Washington has proved to be a door opener. “I’m a lot calmer here than I was in D.C.,” he joked as he sat at lunch with director Cromer, with whom he had become friends, having run into each other and talked theater repeatedly in their Upper West Side neighborhood.

Cromer, a MacArthur Fellow whose own star has risen with his highly regarded New York productions of “Our Town” and “Tribes,” had heard about Colaizzo’s success with “Really Really” at Signature, where it was staged by associate artistic director Matthew Gardiner. The play, revolving around an accusation of rape at a college filled with students looking out only for No. 1, is a scathing commentary on the values of an up-and-coming generation. Offered the chance to direct it in New York, Cromer told Colaizzo he would read it. “I said to him, ‘I have the play,’ ” Cromer recalled. “‘If I don’t do it, it’s not because it isn’t good.’ ”

Three hours later, the anxious Colaizzo received a text message from Cromer, but not about theater: It was related to the social online game “Draw Something” and was misfired to Colaizzo. Both men chuckled over that memory. “Then I got a call from my agent,” Colaizzo said, “that he’s ‘in.’ ”

The major foothold Washington theater can be for a playwright is borne out in Colaizzo’s case. Although the next step for “Really Really” is uncertain, Colaizzo’s has been cemented. This fall, Signature will produce the world premiere of “Pride in the Falls of Autrey Mill,” set in an all-too-perfect suburb, by one Paul Downs Colaizzo. Around such ongoing relationships do the roots of a theater community’s influence feed, and spread.