Neil Sedaka, one of pop’s most enduring songwriters whose career extended from after World War II to the countercultural days of Elton John, has died, his family said Friday.

Sedaka, the writer behind such songs as “Breaking Up is Hard to Do,” “Love Will Keep Us Together” and dozens of other hits, was 86. His cause of death was not clear.

“Our family is devastated by the sudden passing of our beloved husband, father and grandfather, Neil Sedaka,” his family said in a statement to NBC News.

Sedaka got his start in high school, performing with a doo-wop group, the Tokens, that recorded two hit singles. Collaboration with his young neighbor, Howard Greenfield, led to a songwriting partnership that lasted a half-century and resulted in 40 million records sold between 1959 and 1963, according to his official bio.

Connie Francis recorded the duo’s “Stupid Cupid,” putting them on the music industry map in 1959.

“Breaking Up is Hard to Do,” from 1962, epitomized Sedaka’s career at the time. The single he co-wrote with Greenfield features Sedaka’s clear, easy-to-listen-to voice over a traditional song structure at a time of tumult in music, when rock ‘n’ roll was transforming the landscape and starting its domination of radio.

Sedaka never quit and found a way to fit in as music evolved and the counterculture of the late 1960s and 1970s changed the rules and ushered in harder rock, disco, and a new reign of Black music from the likes of Marvin Gaye and Stevie Wonder.

A version of “Breaking Up is Hard to Do,” re-recorded by Sedaka in the mid-1970s was nominated for song of the year at the Grammy Awards in 1977 but was beat, ironically, by “I Write the Songs,” which was performed, but not written, by Barry Manilow.

Sedaka was reintroduced as a performer to music fans by Elton John and his label, Rocket, which released “Sedaka’s Back” in 1974 and “The Hungry Years” in 1975, according to the bio.

In 1995, he leaned on his classical training at Juilliard, where he learned about music at its preparatory division for children at age 8, to release “Classically Sedaka,” according to his bio and a bio from the Long Island Music & Entertainment Hall of Fame.

He would later be inducted into the Songwriters Hall of Fame.

“A true rock and roll legend, an inspiration to millions, but most importantly, at least to those of us who were lucky enough to know him, an incredible human being who will be deeply missed,” his family said in Friday’s statement.