Bobby Rydell, 79, the singer who rose to fame as a South Philly teen idol with hits like “Kissin’ Time,” “Wild One,” and “Wildwood Days,” and maintained a career in show business that lasted six decades, has died.

Mr. Rydell’s death was confirmed by his marketing and event coordinator, Maria Novey, who said he died Tuesday afternoon at Jefferson Abington Hospital.

She said that Mr. Rydell’s death was unexpected, though he had many health problems, dating to 2012 when he underwent a double transplant to replace a liver and a kidney.

Philadelphia DJ Jerry Blavat had booked Mr. Rydell to perform at the Kimmel Center in January, but the singer was unable to perform due to poor health. The cause of death was non-COVID-19-related pneumonia complications, according to Novey. Mr. Rydell’s wife, Linda J. Hoffman, was by his side at the hospital, Blavat said.

Along with Frankie Avalon, Chubby Checker, and Fabian Forte, Mr. Rydell was one of four South Philly teen idols who found a national audience in the late 1950s and early 1960s through Dick Clark’s Philadelphia based television show, American Bandstand.

On Twitter, singer Tommy James called Mr. Rydell “a good friend and one of my idols. He will be sorely missed.” Adam Weiner of the Philadelphia band Low Cut Connie called him “a South Philly legend. ... Bobby did the greatest version of `Volare’ ever.”

Born Robert Ridarelli, he won a talent contest on Paul Whiteman’s TV Teen Club show in 1950 and soon after changed his stage name to Rydell. Before he was out of his teens, he was an international star, touring Australia with the Everly Brothers in 1960 and becoming the youngest performer to ever headline the Copacabana in New York in 1961.

His hits were many, starting when he signed with Philly’s Cameo Records (which would later become Cameo Parkway) in 1959. His first was “Kissin’ Time,” followed by “We Got Love,” his first million seller, and “Little Bitty Girl,” his second. In 1960, he hit it big with a cover version of Domenico Modugno’s “Volare,” and “Wildwood Days,” in 1963, became a song of celebration and nostalgia for generations of Philadelphia-area Jersey Shore-goers.

That same year, he starred opposite Ann-Margret and Dick Van Dyke in the film version of the musical Bye Bye Birdie. His name was so associated with the pre-British Invasion period of vintage rock-and-roll that the school in the 1971 musical and 1978 film Grease was known as Rydell High.

Of all the teen-idol singers, “he had the best pipes,” Blavat said Tuesday. “He could do Sinatra, he could do anything. Listen to “Volare.” He could do comedy. He played the drums. He was a great mimic. He was on The Red Skelton Show many times. He could have been as big as Bobby Darin, but he didn’t want to leave Philadelphia.”

Mr. Rydell’s father, Adrio, began taking him to entertainment venues in South Philadelphia like the RDA Club and Erie Social Club when he was 7, asking if his talented son could sit in and play drums with the house band.

He started out as a crooner in his early teens, before becoming a rock-and-roll sensation who along with Avalon, Fabian, and Checker, helped fill the void for pompadoured teen heartthrobs when Elvis Presley’s career was put on hold when he went in the Army in 1958.

“I was not really a rock-and-roll singer,” Mr. Rydell told The Inquirer in 2016, at the time of the publication of his memoir, Teen Idol on the Rocks: A Tale of Second Chances. “That’s what you had to do to make it. I’m an American Songbook guy.”

If asked for the favorite song in his repertoire, Mr. Rydell would respond without hesitation. It was “Wildwood Days,” the ode to the beach town where, when he was growing up in a rowhouse on 11th Street in South Philly, he could escape to. His grandmother owned a boardinghouse there. “It’s the national anthem of the Jersey Shore,” he said.

When Mr. Rydell’s career took off in 1961, his father resigned from his job as a foreman for the Electro-Nite Carbon Co. to become his road manager. A few years later, Mr. Rydell moved his parents and his grandparents into a house with him in Penn Valley, where he lived until moving to Blue Bell in 2019.

The big hits stopped coming for the Philly teen idols in the mid-1960s, after Bandstand moved to Los Angeles and the Beatles arrived. But Rydell kept performing.

“[I] can’t believe the vocal ability [Rydell] has,” Avalon said in 2016. “As an actor, as a comedian, as an impressionist, rapport with the audience, he is without doubt one of the most talented human beings of my entire generation.”

The title to Mr. Rydell’s memoir referred to his struggles with alcohol, which he said began in 1992 when his first wife, Camille, who died in 2003, was first diagnosed with breast cancer.

“I had no right to feel sorry for myself,” he wrote in Teen Idol. “I knew damn well how I had gotten where I was. Decades of drinking had ravaged my body and wrecked my liver and kidneys. I had no one to blame but yours truly.”

Mr. Rydell married Hoffman, a nurse and X-ray technician, in 2009. After his 20-hour double kidney and liver transplant in 2012, he had heart bypass surgery the next year.

Still, Mr. Rydell, whose face adorns murals in South Philadelphia and Wildwood, kept performing, mostly with Forte and Avalon. With the Golden Boys and as a solo performer, Mr. Rydell averaged about three dozen shows a year leading up to the start of the pandemic. The trio made their return to the stage in Lancaster in August, but Mr. Rydell was unable to perform a show in Florida in January. The singer Lou Christie filled in for him.

A show at the Golden Nugget Hotel & Casino in Atlantic City, originally scheduled for March, had been rescheduled for June, “and we were hoping he would get his strength back to be able to make that show,” said Novey.

Novey first met Mr. Rydell and Hoffman on a Malt Shop Memories Cruise where he was performing “and he just sat and talked and took pictures with everybody,” Novey said. “He was just a Philadelphia guy who never forgot where he came from. I never saw him turn down a request for an autograph, and I mean never. We’d be waiting for the car, and he’d sign an autograph on the roof. He was just so appreciative, and he certainly didn’t have an ego.”

In addition to his wife, Mr. Rydell is survived by his daughter, Jennifer Dulin, and son, Robert Ridarelli, and five grandchildren. No funeral or memorial service arrangements have been made at this time.