As Rep. Frank D. Lucas leaned back in the barber’s burgundy chair one recent afternoon, he mentioned that he and the man wielding the shears above his head have a bit in common.

“If you don’t like people, you’re not going to be a barber,” drawled the Oklahoma Republican as he got a trim. “Or you’re not going to be a member of Congress.”

As a House of Representatives barber, Giuseppe “Joe” Quattrone has spent 42 years expertly maneuvering his scissors around the ears and bald patches of Republicans and Democrats with equal finesse. In a world of white marble, he regularly deals with shades of gray — mostly of the salt-and-pepper variety.

The 78-year-old barber, an Italian immigrant, offers a piece of panettone or a slice of sopressata to the lawmakers, staff and visitors who have been coming to his basement shop in the Rayburn House Office Building since 1970.

For those who call the dome home, “Joe Q” is an institution.

“He is kind of living history,” said Lucas, among those who stopped by on a Tuesday early this month. “He may not know it, but he can never retire.”

Quattrone has cut the hair of most of the House speakers since Watergate. (Not, however, Nancy Pelosi or John Boehner.) But he doesn’t trade gossip and never talks politics. Instead his clients find themselves bathed in the sweet smell of aftershave, lulled into relaxation by the low hum of the No. 1 razor.

But it’s not just the atmosphere — which includes dark walls lined with dozens of framed, autographed pictures of politicians Quattrone’s met over his nearly half-century there — that keeps them coming back.

It’s Quattrone himself, the man with the eggshell blue smock, the wispy white ponytail and a comb in his breast pocket that’s missing a few teeth.

He offers “a great haircut, but it’s more than a haircut,” said Howard A. Denis, senior counsel for the House Committee on Oversight and Government Reform. “A la famiglia.”

­­Quattrone is a mentor and friend to many of those who work on the Hill, who often stop by long after their hair’s gone.

Michael Nelson, the Navy chief of the Office of Legislative Affairs, who came by that Tuesday from his office across the hall, can often be found in the barbershop even though he sports a shaved head. Richard Pecantte, a legislative assistant to Rep. William Lacy Clay (D-Mo.), dropped in for a cigarette and a powdered doughnut.

“This is a family barbershop,” Quattrone said in his barely accented English. “We got a lot of friends who come in, shoot the breeze.”

Later that day, Rep. Bill Pascrell Jr. (D-N.J.) ducked in for a quick visit.

Quattrone stopped to hug the congressman and kiss his cheek. “He’s my dearest friend,” Quattrone said.

Pascrell passed the barber a bottle of wine he brought as a gift. “We’ll talk tomorrow,” he called over his shoulder before heading out.

Although Quattrone doesn’t weigh in on political debates, he hears about them in between the staccato snips of his scissors. With congressional approval ratings at an all-time low, he defends his lawmaker friends and advises constituents to come talk to their representatives.

“I’ll tell you, they work really hard. They have a tough job,” he said. “They earn their money, believe me.”

Some of his clients are much newer to the political scene.

McLain Faett, 16, took his turn in Quattrone’s chair after a day spent lobbying with his mother for Reach Out and Read, a national nonprofit organization that promotes early literacy.

After a few errant hairs toward the back of his brown head were taken care of, McLain asked hesitantly whether he could get a shave, too.

“Can I give you advice?” Quattrone asked the fresh-faced teenager. “Unless you have to, don’t do it.”

McLain shrugged off his disappointment while his mom laughed. “I always wanted to get a shave by a barber,” he said, giving up.

Quattrone began cutting hair in Italy when he was not much younger than McLain, 12 or 13 years old, he said. It was mostly so he could get out of working on the family farm — a job he hated.

“That’s one of the reasons why I came here,” he said.

He originally joined his brother and uncle in Ohio in 1952 and later moved to the District, where he got his job as a House barber by contacting his congressman. By the 1980s, he was managing the shop, which was privatized in the mid-1990s.

After Sept. 11, 2001, he saw business drop off, mainly because of increased security in the building. “People can’t come in and out like they used to,” he said.

When Quattrone began cutting hair on the Hill, there were five barbershops on the House side, employing 14 barbers, four shoe-shine men and three manicurists. Now there’s just his shop, where he works with one other full-time barber, one part-timer and a shoe-shine man.

“I think it’s one of the best jobs a barber can have,” Quattrone said. “I got the most famous people, the most important people. And I’m a part of it.”

To his clients, he’s a big part.

Each Christmas, Quattrone and his crew throw open their door and pass out plates for a huge hallway party with pasta, meatballs and Quattrone’s homemade sausage. “Everybody that passes by, we make them stop,” he said.

But despite the personal ties that span 42 years, there are some things Quattrone still keeps close to his smock.

“Someday,” Lucas said with a sigh, “I’m going to get him to admit his sausage recipe.”