Playing a stage version of the Kevin Bacon "degrees of separation" game, you could hardly do better than to use Jennifer Harmon, who's back in Pittsburgh to appear in Jeffrey Hatcher's "Murderers" at City Theatre.

If her name sounds familiar, you may remember when she starred here over three summers -- 1983 through '85 -- for the ambitious, mold-breaking American Ibsen Theater. For that, she was named Post-Gazette Performer of the Year in 1985-86.

But what puts Harmon in the Kevin Bacon hall of fame is the rest of her long career -- in tours, regional theater, New York and, above all, understudying or standing by on Broadway for such well-connected luminaries as Judi Dench, Blythe Danner, Jessica Lange, Stockard Channing, Judith Ivey, Marian Seldes, Rosemary Harris, Jill Clayburgh and Jessica Walters.

And that doesn't begin to name the hundreds she's acted with, such as on her very first visit to Pittsburgh, in the farewell 1967 tour of Helen Hayes (now there's a name!). In every city, "the first thing she'd do was get the local newspaper and post a schedule for each day," Harmon recalls. "We'd do wonderful things"

Standing by (which is what you do when you're too established to understudy) has some cachet and earns good money, but "sitting on the bench and watching everyone else play," as Harmon puts it, isn't her first choice. So when a friend, director Michael Bush, called to suggest she come to Pittsburgh to do "Murderers," she was game.

It helped that she had fond memories of Pittsburgh, even though she spent those three summers ensconced at Chatham College, where the Ibsen Theater performed. City has her in a zestier section of town, elegantly housed in a big, airy South Side apartment building -- the former Polska Szkola, built in 1898 and now divided into condos. Her unit even comes with her own stage.

"People don't believe it when I tell them," she says over coffee on Carson Street, "but when they walk in they say, 'You do have a stage!' " She sure does. It's the stage end of what used to be an auditorium, with tall windows looking eastward over the rooftops of the South Side. She loves that and has even learned to like the trains that thunder right past.

In spite of the hard work of rehearsing what is actually a very long monologue, this inveterate walker has been exploring in ever widening arcs -- now the Mon riverbank, next week Oakland, then Shadyside, the Hill and Point Breeze. Those last two are because of her passion for the work of August Wilson and Annie Dillard, Pittsburgh authors born just three days apart but living in very different parts of town and cultural circumstances.

Harmon is a glutton for all kinds of social and literary history, so it takes much discussion of Andrew Carnegie, libraries, organs, the Pinkertons and steel, not to mention "Murderers," before digging into her theatrical life.

"Murderers," the sixth play City has done by Hatcher, is described as "golden girls go wild'' in a comedy set in a luxury senior retirement and golf center in Florida. Harmon plays pert, elderly Lucy; Daniel Krell plays the scheming Gerald; and Sheila McKenna (a more recent PG Performer of the Year) plays Minka, the vigilante. The show begins previews tonight in the 111-seat Lester Hamburg Studio and already has been extended through Dec. 22.

Harmon's story isn't just theater, but even to sketch it, you need to go back to her youth in New Orleans. As soon as you hear that, it sounds right, because her diminutive, fragile beauty could well be that of a Southern belle, lacking only the accent.

She grew up in the French Quarter and the Garden District with a father from Mississippi and a mother from New England: "We had the Civil War in my family." She caught the theater bug in high school, finding acting and dance gave her a voice. Partly because her father died when she was 15, she honored his wishes and went to the University of Mississippi -- and happened to be there in 1962 when integration came to Ole Miss in the persons of James Meredith, lots of U.S. marshals and hordes of angry bigots.

What follows is an epic story that Harmon really ought to write. In short, her upbringing (including a black nursemaid), her friends and the theater environment all resulted in her being the one female to join six male students at lunch with the ostracized, embattled Meredith ("the bravest man I've ever known").

As a result, three of the men were beaten, her dorm room was wrecked and friends terrorized, there were death threats and she had her own marshals for a couple of weeks. "New Orleans had its problems, but Mississippi was a dark, scary place. The White Citizens Council was real, the Klan was real, there were lynchings" -- even though you'd see William Faulkner walking the streets.

So she left Mississippi for the University of Michigan. There, Ellis Rabb and the APA-Phoenix Theater saw her in "The Importance of Being Ernest." Her pro career already had begun in professional summer stock on Cape Cod. But it was jump-started in earnest when she left college in 1964 to join the classical repertory company that toured and did residencies, including annual visits to Broadway's Lyceum Theater. There, Harmon made her Broadway debut in 1965 as Essie in "You Can't Take It With You."

"That was my real training," she says. Her accent was beaten out of her by legendary voice teacher Edith Skinner, who ruled American theatrical voice training from 1937 to 1974 from her imperious perch at Carnegie Tech and later at New York's Juilliard School, and who worked extensively with APR-Phoenix.

"I think I drove her to drink, getting rid of my Southern accent," Harmon says, although stories testify that Skinner didn't need to learn to drink from her.

Harmon was on Broadway regularly in those APA-Phoenix years, the '60s, playing mainly classics. She married a painter for a while and lived two years in Portugal, because it was cheap with beautiful light. ("I had to take three buses to get to market, came home with an octopus and had to learn to skin and cook it.") She returned to play Ophelia in Washington, D.C., then started doing modern plays and soap operas and even lived in Los Angeles. Mainly, she spent 10 years playing in all the leading regional theaters, "doing marvelous roles but coming back with no money."

Her re-emergence on Broadway came about mainly because she needed money and medical insurance because of health problems. Sometimes, she was able to take over the role she backed up, as with Ivey's in "Blithe Spirit," or at least play the role a few times, as she did for Lange in "The Glass Menagerie."

As to understudying Dench in David Hare's "Amy's View," she learned one afternoon she'd have to go on that night, because Dench's husband was sick and she had to fly back to England. She and a producer friend grabbed a cab to race to the theater, but he stopped it at a newsstand. She complained until he pointed out he was buying her a pack of cigarettes because that night on stage she'd have to smoke for the first time in 20 years.

"Thank god I had watched Judi like a hawk," she says. "She's such a magnificent physical comic."

The health problem that kept Harmon close to home (and that her father died of at 53) led six years ago to a liberating kidney transplant, made possible by Caitlin O'Connell. She sings the praises of this "guardian angel, who gave me a kidney and saved my life," and the Robert Wood Johnson Medical Center in New Brunswick, N.J. And she urges everyone to consider being a donor.

"It's a miracle story," she says. "Now, I just want to work. ... Acting isn't the easiest life, but what's thrilling about it, for someone saddened by not finishing college, your education is continual."