Marty Balin, a co-founder of Jefferson Airplane and a member of its later incarnation Jefferson Starship, whose high and soulful voice defined many of both groups’ songs, died Thursday, his rep confirmed. He was 76; the cause of death was not announced.

His wife, Susan Joy Balin, was “by his side,” according to the announcement.

Although Balin had his greatest impact as one of the architects of the musical counterculture during his 1965-71 tenure in Jefferson Airplane, he had his greatest commercial success when he rejoined the remnants of that group a few years later in Jefferson Starship, as the sole lead singer on both of that band’s singles to reach the top 10, “Miracles” in 1975 and “Count on Me” in 1978.

He was a member of the Rock & Roll Hall of Fame, having been inducted with other members of the Airplane in 1996. It was 20 years later that the band received the Recording Academy’s lifetime achievement award, with Patti Smith writing in the Grammy Awards’ program book about her appreciation for “the soaring combination of Grace Slick’s acerbic wit and fearless charisma and the romantic purity of Marty Balin.”

Born Martyn Jerel Buchwald, Balin was a young folksinger in San Francisco when he formed a band with fellow folkie Paul Kantner, who specialized in 12-string guitar. The pair teamed up with guitarist Jorma Kaukonen, bassist Jack Casady, drummer Skip Spence and singer Signe Anderson as the Jefferson Airplane and released their debut album, “Jefferson Airplane Takes Off,” in 1966. Anderson and Spence soon left the band and were replaced by Grace Slick and Spencer Dryden, respectively, and the group’s 1967 album “Surrealistic Pillow” — featuring the Slick-sung hits “White Rabbit” and “Somebody to Love,” along with several songs co-written by Balin — vaulted the group into superstardom. The harmonies between Slick, Balin and Kantner became a signature of the group’s sound.

Balin was a galvanizing member of both the band and the San Francisco scene, and in 1965 helped launch a club in the city called the Matrix that hosted many groups of the era, ranging from the Airplane, the Doors and Janis Joplin to the Velvet Underground. He sold his interest in the club after the Airplane’s star began to rise.

Jefferson Airplane issued several more albums into the early 1970s and played at both Woodstock and Altamont (where he was famously knocked out by a Hell’s Angel after trying to intervene amid the violence).

The group splintered in the early 1970s but several members, including Slick and Kantner, reunited as Jefferson Starship in the mid-‘70s, and Balin was persuaded to reunite with his former partners during the recording of their debut album. His high tenor voice became a centerpiece of the group’s sound via hits like “Miracles” and “With Your Love.” That group splintered as well before reuniting without Balin several years later as a pure pop outfit under the abbreviated name Starship.

Balin went solo and enjoyed a top 10 hit of his own in 1981 with the song “Hearts.” In 1989, he joined up with a short-lived Airplane reunion tour and returned four years later to Jefferson Starship, finally leaving for good in 2008. His final solo album, “The Greatest Love,” was released in early 2016.

He underwent open-heart surgery in 2016 and later sued New York’s Mount Sinai Beth Israel Hospital for medical malpractice, claiming multiple injuries from the operations. Balin’s illness rendered him unable to attend the Grammys when the Airplane was awarded lifetime achievement honors, but he released a statement at the time, saying, “”I am grateful for the beautiful musical journey my life continues to take. To all my fellow Jefferson Airplane Band members, through its various metamorphoses, I thank you for a dream come true.”

In a statement, Susan and Balin’s family issued a statement that noted how Balin “also enjoyed painting all his life. He painted vibrant, large-scale portraits of many of the most influential musicians and good friends Janis Joplin, Jim Morrison and Jerry Garcia, to name a few.”

“Marty was the one who started the San Francisco scene,” says Bill Thompson, Balin’s roommate back in the mid-’60s and former manager of both Jefferson Airplane and Jefferson Starship.

“Back in those days Marty was quite the businessman,” said Paul Kantner, who passed away in 2016. “He was the leader of the band on that level. He was the one who pushed us to do all the business stuff, orchestrating, thinking ahead, looking for managers and club opportunities. He was very good at it.”

Balin is survived by Susan, daughters Jennifer Edwards and Delaney Balin, and stepdaughters Rebekah Geier and Moriah Geier.

“Marty and I shared the deepest of love — he often called it Nirvana — and it was,” Susan Balin said in a statement. “But really, we were all touched by his love. His presence will be within my entire being forever.”