Irish-born actress Fiona Shaw, artist-in-residence for the Kennedy Center’s Irish celebration. (Jon Enoch/Courtesy of the Kennedy Center)

Irish-born actress Fiona Shaw describes her homeland this way: “Hopeful. Optimistic. Brilliantly educated. With a small population, it can mend its problems quite quickly. It’s a very good economic model of a country, because it has as few people as you have many.”

If that sounds as though Shaw is playing the ambassador, perhaps it’s because she is traveling to Washington as the artist-in-residence for “Ireland 100: Celebrating a Century of Irish Arts and Culture.” Starting Tuesday, the festival will inhabit the Kennedy Center for three weeks of literary events, dance, music and theater — more than 50 performances and 500 performers.

The fabled Abbey Theatre will offer Sean O’Casey’s great Easter Rising drama “The Plough and the Stars.” Colin Dunne and Jean Butler (early “Riverdance” stars) each have events, and opera singers Tara Erraught and Anthony Kearns will share a concert. Installations include “The Earth Harp,” billed as the world’s largest stringed instrument (it will be in the Hall of States), and the immersive “A Girl’s Bedroom” from writer-director Enda Walsh, a free 20-minute experience in the Terrace Gallery for only five people at a time.

The center’s north plaza will become a “green space” for performances by fiddlers, pipers and step dancers. Food trucks will service the green space much of the time: Fish and chips and Guinness are promised.

Shaw herself will be amply deployed. The world-class stage performer — whose past Kennedy Center appearances include “Medea” and Samuel Beckett’s “Happy Days” — directs the gala opening concert, moderates a panel on Shakespeare’s future and leads an acting master class. Befitting someone whose performance of T.S. Eliot’s “The Waste Land,” according to Post critic Peter Marks, “is regarded as a landmark in the genre of solo performance,” Shaw also will debut her own new piece, “Blowing the Heart Open,” combining the poetry of Ireland’s W.B. Yeats and America’s Emily Dickinson.

Tony Flynn and Joe Hanley in the Abbey Theatre’s production of “The Plough and the Stars,” by Sean O’Casey. (Ros Kavanagh/Courtesy of the Kennedy Center)

“As she died, he was coming into adulthood,” Shaw says by phone from London, her voice light and crisp. “One gives way to the other. She was fragmented, wasn’t she? And he was an ebullient and extravagant writer. I don’t know any two poets who speak so directly to the reader. They’re like rock stars.”

The festival is keyed to the 1916 Easter Rising — “quite an amateur revolution,” Shaw says of the ragtag rebels overmatched by trained British forces. “But it was an incredibly important moment in Irish history after 500 or 600 years of being horribly repressed.”

The 50-year anniversary in 1966 had a defiant tone that Shaw describes as “jingoistic” and “militant.” “A young state trying to show off,” she says. “Wisely, now in Dublin the posters all say ‘Reflect.’ It’s a most brilliant idea.”

Directing the opening concert might not seem like an obvious endeavor, yet in recent years Shaw has helmed major operatic productions in England and stateside at the Metropolitan Opera. The transition reflects a bit of a shift: Shaw is now 57, and she recently realized she’d like to decelerate her taxing habit of rehearsing and performing high-intensity characters.

Those challenges include the title role in the 1995 “Richard II” for London’s National Theatre (it was filmed by director Deborah Warner, Shaw’s frequent collaborator, in 1997). Cross-gender Shakespeare is now the rage — an all-male “Taming of the Shrew” starts Tuesday at the Shakespeare Theatre Company, and an all-female “Shrew” opens this month in New York — although Shaw cautions that hers was not a wholesale radical rethink.

“Richard II is such an effeminate king that it was only one tiny step — just me as an effeminate person in that play,” Shaw says. “Now the eye and ear of the audience seem much more tolerant of hearing the opposite gender for whom the characters were written.”

Shaw’s pop culture credits are few, but substantial. She was Aunt Petunia in the “Harry Potter” franchise and has lately been seen as the witch Marnie Stonebrook in “True Blood,” which she thinks may have come her way because she was once the demonic Medea. Illustrating how far apart the poles of an actor’s life can be, Shaw was offered Marnie Stonebrook while appearing in Henrik Ibsen’s daunting drama “John Gabriel Borkman” for the Abbey with Lindsay Duncan and Alan Rickman.

“To my great chagrin,” Shaw recalls, “I said, ‘What is ‘True Blood’?”

It was a fresh step for a performer who has made change her hallmark. “I have tried always to do things very different from what I’d just done,” she says. After playing Electra in 1992, Shaw steered clear of Greek drama for about a decade. She did the same after triumphs in roles by Ibsen, Brecht and Shakespeare. “I think it’s the only way to find a new mountain range to climb.”

Ireland 100: Celebrating a Century of Irish Arts and Culture May 17 to June 5 throughout the Kennedy Center. Call 202-467-4600 or visit kennedy-center.org.