How’d Peter Gallagher get in this room?

Peter Gallagher read poetry, sang and watched football with Peter O’Toole.

At the start of every interaction, when asked how he was, the “Lawrence of Arabia” star would reply, “Gruesome,” Gallagher recalled.

To the young actor, Jack Lemmon was like a second father who, with trademark generosity, gave Gallagher his first set of golf clubs.

During their regular meetings, Lemmon — “Some Like It Hot,” “Days of Wine and Roses” — would ask, “You got anything lined up, kid?”

When Gallagher replied in the negative, the venerable actor would say, “Me neither.”

After three-plus decades as a performer, the 58-year-old, who played Sandy Cohen in Fox Network’s “The O.C.,” is convinced that these experiences will bring smiles to his face right up until he is on his deathbed. It’s the people in the room who matter, he said, and everything else is a “crap shoot.”

“The thing that’s of the greatest value to me has nothing to do with whether my shows were hits or flops, or whether they earned or lost money,” Gallagher said. “It was these moments along the way with truly wonderful people that gave me something that will stay with me forever.”

He was fortunate, he reflected, to come along when the legends were still alive, adding, “The greatest artists I’ve been lucky enough to work with have also been the easiest [to work with] and the kindest.”

In 2007, Gallagher was approached by the team at the now-defunct Feinstein’s at Loews Regency with a request for him to do a one-man show. Having just completed a project, the New York City native was filling his down time by singing and writing. Right away, his treasured interactions with Hollywood’s greats came to mind, and “How’d All You People Get In My Room?” — fashioned after a Dean Martin monologue — was born.

Thursday will mark Gallagher’s debut at the Segerstrom Center for the Arts’ Samueli Theater, where he will present the “grandchild of the original show.” A four-piece band will accompany the Tony nominee as he performs tunes from Broadway and “The O.C.” as well as popular classics by Sammy Cahn, Jules Styne, Burt Bacharach and Van Morrison. At the intimate concert, guests will be able to dine while being regaled with anecdotes about Lemmon, O’Toole, James Cagney, Mike Nichols, Robert Altman and others.

Terry Dwyer, president of the Costa Mesa arts complex, claims to be “jealous” of Gallagher, who plays a lead role in one of his favorite dramas, “Covert Affairs.”

“I admire a Broadway actor who’s done TV shows and has a great movie career too,” Dwyer said. “He’s the renaissance man of the performing arts. Peter is an engaging conversationalist with a warm personality, and the audience is going to really enjoy getting to know him.”

When asked what sets the star of stage, television and screen — “American Beauty,” “While you Were Sleeping” — apart from other current faces, Dwyer responded, “The flip answer would be a lot of talent.”

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A tough ‘Room’ to face

Gallagher worked hard to ensure that his act was not a recitation of his resume. He’d rather jump in front of moving traffic, he murmured. But unlike the familiar experience of disappearing into one of his roles, he felt exposed and vulnerable with his own words and stories. Stepping out for the inaugural performance of “How’d All You People Get In My Room?” was easily the scariest experience of his life, he remarked.

Today, nearly seven years after that first show, Gallagher acknowledged that the rewards — not the least of which was his first brush with complete creative freedom — were rich.

“This is the essence of what I love about what we do, which is storytelling,” he said. “Sometimes, when all the elements are right and it works, there’s no better feeling. It makes people feel included and reminds us that we’re all members of the same tribe. It’s so powerful.”

Gallagher’s pursuit of an acting career would have seemed an atypical choice in his family. His mother was a bacteriologist and his father served in World War II and went on to work in advertising. The dad belonged to the first generation in his family to work above ground — his father was a coal miner.

Gallagher was involved in theater at Byram Hills High School and went on to study at Tufts University and join the Boston Shakespeare Company.

Planning to graduate early, he spent a summer at UC Berkeley, where he elected to study non-Western economic thought and statistics. Then it hit him. There is power in a room filled with people, lights, music and a story — and the mere thought of living without that power was excruciating.

Gallagher gave himself seven years to make a living onstage. Soon thereafter, an open call landed him a role in “Hair” in New York City. To this day, Gallagher remembers — and questions his audacity for — approaching director Tim O’Horgan and asking to leave to play Danny Zuko in the touring company of “Grease.”

“I didn’t know any better and it seemed to make sense at the time,” he said about his quest to travel. “If I’d had an agent, it would not have been possible. I didn’t read signed contracts. I just signed on the dotted line.”

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The book of Lemmon

Gallagher, who is poised to return to “Covert Affairs” for its fifth season on the USA Network and, in the fall, to Broadway with Kristin Chenoweth for “On the Twentieth Century,” looks back on his contribution to “The O.C.” with pride.

Post-9/11 America was a different place, he said, with its spasms of xenophobia, climate of fear and people mistrusting their neighbors. So he decided to play a liberal Jew from Brooklyn, living in conservative Newport Beach, who not only retains his values and sense of humor but also warmly welcomes an outsider, which he labels a “genuinely American thing” to do.

“Even today, people on Twitter, Facebook and on the street want to talk about ‘The O.C.’ and Sandy Cohen,” Gallagher remarked. “I’m so lucky to have been part of a story that found a place in the world we live in and resonated with people.”

It served the Golden Globe and Screen Actors Guild Award recipient well, he reflected, to take a page from Lemmon’s book and always be ready for “one more take, one more role and one more chance.” It’s about getting up to bat, he believes.

Nowadays, it’s harder than ever to make a living as a performer, Gallagher noted. Having always worked with an acting and voice coach, he reminded aspiring actors to find dedicated teachers, to continue learning and showing up and to arm themselves with a “strong capacity for self-delusion.”

“You have to keep the love for what you’re doing alive,” he said. “Money and recognition come and go, and hopefully come again. But if they don’t, if you get another crack to do what you love, that’s good, and if you can support your family, that’s a miracle.”

If You Go

What: Peter Gallagher: “How’d All You People Get In My Room?”

Where: Samueli Theater, Segerstrom Center for the Arts, 615 Town Center Drive, Costa Mesa

When: 7:30 p.m. Thursday till Saturday

Cost: Tickets start at $79

Information: https://www.scfta.org or (714) 556-2787