“He’s a treasure,” said Sean Sardi Ricketts, 37, a co-owner of the restaurant, the great-grandson of Vincent Sardi Sr. and the grandson of Vincent Sardi Jr., who took over the restaurant when his father retired and helped make it a Broadway institution. “He’s not even a customer on Tuesdays. He’s like part of the family.”

Image William Herz, left, at Sardi’s last Tuesday for lunch with members of the Dutch Treat Club, a 105-year-old organization of writers, artists and performers that he once belonged to. Credit... Fred R. Conrad/The New York Times

Sardi’s has long been at the center of Broadway life — the idea for the Tony Awards was born there over lunch, according to Vincent Sr.’s 1953 book — and Mr. Herz said it was only natural for it to become the center of his life as well. And there is another reason he has been returning to Sardi’s for roughly 77 years.

Shortly before a play he had produced closed after just a week at the Lyceum Theater in 1940, Mr. Herz was eating at Sardi’s when Vincent Sr. asked him to join him for dessert and coffee. “And he said to me, ‘I know your show is closing,’ ” Mr. Herz recalled. “He said, ‘I just want you to keep coming to Sardi’s, and don’t worry about the bill.’ So I burst into tears, and that’s why I’ve been a customer of Sardi’s for so long. I was touched and moved by it, and I thought it was damn nice of him.”

These days, Mr. Herz picks up his own bill.

Hundreds of theater, film and television personalities have had their caricatures up on the walls of Sardi’s, but Mr. Herz is not one of them. Like most New Yorkers who regularly dine in what is perhaps the restaurant capital of the world, he is not as famous as the place where he eats lunch. He was an extra, occasional actor, stage manager, casting director and producer on Broadway through the 1930s and 1940s, and then worked for years at a ticket agency next door, naturally, to Sardi’s.

He is an unpretentious sort who takes the bus to and from Sardi’s and who eats only half of his roasted chicken, because he likes to take the rest home to feed to his dog, Diego. As he sits with his friends at table No. 4, the tourists sitting nearby admiring the caricatures have no idea that the old, frail man in the corner could tell them a story or two about some of the stars on the walls. He does not boast about his career and the theatrical history he took part in — he is the last living cast member of Mr. Welles’s “War of the Worlds” adaptation — but, if asked, he will dish.

There was the time when Mr. Herz was serving in the military during World War II and helped organize a show in Miami for thousands of servicemen featuring Rita Hayworth. “She arrived at Servicemen’s Pier and took off her mink coat — it was a chilly night — and she had a gingham dress on,” he said. “I looked at her and I said: ‘You’re a pinup. Why are you in a gingham dress?’ A housewife would wear a gingham dress in the kitchen. I took her back to the Roney Plaza. She got into an evening gown. She didn’t speak to me the rest of the evening.”