Rosemary Clooney once said, "Any actor can fall flat on his face, but only a professional knows how to get up." By that standard, and many others, Liz McCartney, who plays head nurse Lt. Genevieve Marshall in South Pacificand who performs a one-woman show about Clooney in her rare spare time, is truly a pro.

McCartney's spill happened last summer, shortly after she joined the "SP" cast. "God," McCartney exclaims, an entity she knows well from her five years in the 1990s in Nunsense, "that moment was so embarrassing. I tripped as we nurses were coming back through the Seabees. Thank heaven Victor Hawks" -- Stewpot at the time -- "was there to pick me up. One of the other nurses, Becca Ayers, told me later that lying there I formed a perfect police-drawn chalk outline."

That wasn't the only crime scene in McCartney's impressive and lively career, which in addition to the years in nun's habit included a half-decade as Carlotta in Phantom of the Opera. "I was in Dance of the Vampires, she confesses, "in 2002. It was a well-deserved Broadway flop, a crime against musical theater. It was terrible but hilarious."

Then there is Souvenir, the musical play about the monumentally unselfaware diva Florence Foster Jenkins, which is hilarious and decidedly not terrible. The show, a critical if not commercial success when it debuted on Broadway in 2005, has gone to become one of the most produced professional shows in the United States. McCartney has portrayed Florence in Portland, Maine, and at the George Street Theatre in New Brunswick, New Jersey. (McCartney lives in Bloomfield, New Jersey, with her husband, Tom Moynahan, and their young daughters, Megan and Keira.)

"I would do Souvenir again, happily," McCartney says. "It's probably my favorite role to date. I see it as kind of a prequel to American Idol: Florence is like one of the 'Idol' kids who think they're the best voices on the planet but who really can't sing a note."

McCartney appeared in another show that's gone on to cult status, Taboo, and with that one she was in the original Broadway cast. "It isn't considered a success," she says, "but it was of one of my best experiences."

McCartney says that she has great affection for her South Pacific character, Lt. Marshall: "I love that the Seabees have to salute me." And the actress ladles praise on all her "SP" colleagues: "It's rare in a long run for there not to be at least a little envy and bitterness in a cast, eventually, and there really isn't in this show. I'm having a great time."

BRENDAN LEMON is the American theater critic for the Financial Times and the editor of lemonwade.com