But over the past couple of months, the younger Chios has negotiated a deal to sell the popular institution - name, wooden bar and all - to local businessman Drew Johnson. The deal should be completed this week.
The 62-year-old Chios, called "Junior" by the regulars, said he was tired, and ready "to smell the roses" by traveling to Athens, Florida and California.
His patrons, many of whom are not accustomed to change in their compact, neighborly town of about 4,300, are going to miss him.
"It's disappointing that he's leaving," said Bill Quinn, a 57-year-old painter who has visited the popular tavern nearly every day for the last 30 years.
"People come in here to see Marios. The mainstay was Marios."
As the new owner, Johnson says, he'll keep the black-and-white autographed photos cluttering the mustard-colored walls, the pinkish lights that illuminate the wooden booths, and most of the menu.
Nevertheless, the sale of The Greeks has made some Narberth residents think about what their town is and what it should be.
While the family character of the town seems intact, a wave of newcomers and younger residents and businesspeople appears to be softly nudging this sleepy borough awake.
"Narberth is missing this energy," said Greg Wax, who owns the single- screen Narberth Movie Theater and the Balcony Cafe beside it. "It's definitely an older mind-set in the government. The government doesn't like change."
Rather than a continuation of the old ways, Wax wants something hipper for Narberth, perhaps a scaled-down version of Philadelphia's trendy Manayunk.
"When you open a restaurant in Manayunk, everybody knows about it," Wax said. "But people who live here don't even know we're here."
Sounding a theme echoed by several other new business owners in the district, Wax said Narberth needed to loosen its grasp on old-fashioned ways and concentrate on plans to make downtown more customer-friendly.
"There's a certain amount of charm," Wax said of the district, "but you can have all the charm and it's gone when you get that parking ticket on your car."
Sam Rennix, owner of Wolfes Pool Supplies, is also itching for a change.
"Nothing has changed in the past 100 years except that this street is now one-way," Rennix said, pointing to Haverford Avenue.
Even Mayor Dennis Sharkey has been tossing about an idea to start a downtown revitalization, intended to spruce up downtown storefronts and find new tenants for two shops destroyed by fire last year. But as with any movement toward change, convincing others of its necessity has not always been easy.
"If it's not broken, don't fix it," said Ken Bawden, 58, matter-of-factly as he finished a hamburger at The Greeks.
"The people who live here try really hard to preserve what's here. People in my generation are people of habit. You don't want to see it change."
Beyond the business district, even Narberth's neighborhoods have stubbornly held on to their regulars.
"The older people like myself, they don't move; they die off," said 75- year-old Elliott Shaw.
And though change may lure a new breed of customers to the borough's business district, even some of the newcomers embrace the old ways.
"The parts that are stuck in the past are the parts people want to keep in the past," said Louise Culver, who with her husband and young son moved to the borough a year ago from West Philadelphia. Narberth, she said, "is conscious of community."
Residents and businesspeople alike fear that by altering the makeup of the downtown, the borough's beloved character will disappear.
It's that fear, combined with a hesitancy to challenge success, that has convinced The Greeks' new owner to stick with the old formula.
"I grew up in Wynnewood and spent a lot of time in Narberth," said Johnson. "(The Greeks) has always appealed to me as a local gathering spot of an eclectic group of people."
He hopes he can maintain that appeal, even without the popular Chios around.
"It's a risk. I understand that," Johnson said. "I'm very nervous about filling the shoes of Junior. The best way to do it is to stay calm."
Chios downplayed his role in the tavern's success, saying that the bar's tradition in the borough would be enough to keep it going, even with the change of ownership.
"People come in here to relax and have no aggravation," he said.
"Where else are you going to get that?"