“My brother added a little riff,” said Joe Sherwood, 70, who began singing: “Here they come! Deedley deedley deeeee!”

Williams, the Sixers’ general manager, appreciated how the song turned out — it was exactly what he wanted, he said — but the team kept its rollout subtle.

“It really wasn’t a big deal,” Sherwood said. “There wasn’t any big hoopla or major announcement. They just started playing it.”

World B. Free, 64, a former guard who now works as an ambassador for the team, was a first-year player when the song made its debut. Before home games, the song’s first few beats would reach the players as they took the floor. It became an even bigger deal once Erving, known as Dr. J, joined the team the next season.

“We’d be coming out of the tunnel and the crowd would be getting juiced up,” Free said. “And then Doc would come out there with that big ol’ Afro and start throwing it down: Boom!”

For better or for worse, the song has stuck with Free through the decades.

“I hear it in my sleep,” he said.

In the wake of “Here Come the Sixers,” other teams reached out to the band to write their theme songs, including one for the N.H.L.’s Washington Capitals called “Clap for the Caps.” But none of them had much staying power. And when Williams left the 76ers organization in 1986, the song more or less left with him.