Paul Kantner, one of the founding members of Jefferson Airplane and Jefferson Starship, died on Thursday aged 74.

The San Francisco Chronicle was the first to report his death.

Kantner died from multiple organ failure and septic shock after suffering a heart attack earlier this week, the newspaper said, citing the band's publicist, Cynthia Bowman.

The guitarist formed Jefferson Airplane in the mid-1960s in San Francisco with musicians including Grace Slick, Marty Balin and Jorma Kaukonen. The psychedelic band scored hits with Somebody to Love and White Rabbit

Along with The Grateful Dead, Janis Joplin and Country Joe and the Fish, the band became synonymous with music in the city and its surroundings, with regular gigs at the Fillmore West as well as outdoor shows in the area.

The band advocated sex, psychedelic drugs, rebellion and a communal lifestyle, operating out of an eccentric, Colonial Revival house near Haight-Ashbury. Its members supported various political and social causes and tossed out LSD at concerts.

Kantner became the conscience of the band and by the end of the 1960s was shaping its increasingly radical direction, whether co-writing the militant Volunteers with Balin or inserting a profane taunt into his own incendiary We Can Be Together, leading to an extended fight with their record company, RCA.

Jefferson Airplane were major attractions at the Monterey Pop and Woodstock music festivals, and played at the infamous Altamont concert headlined by the Rolling Stones in San Francisco in 1969.

The band split in 1972 and Kantner and Slick led a reconstituted lineup as Jefferson Starship.

Balin would rejoin his former bandmates a few years later, and the band shifted its sound, finding favour on album-oriented rock and middle-of-the-road radio stations. They enjoyed a No. 1 smash in 1975 with Miracles, and top 20 hits over the next few years with With Your Love, Count on Me and Runaway.

Jefferson Starship

Members of Jefferson Starship are shown in an undated 1970s photo, with Paul Kantner on the far right. (Hulton Archive/Getty Images)

With a number of talented and headstrong members, the group was a balancing act, Kantner told Creem Magazine in 1975.

"It's a group," Kantner said. "Anarchistic democracy. The Airplane was the same way. I don't dictate anything and neither does anybody else. Usually, we do stuff because more of the people want to do it than less. There's usually never total agreement on things."

Kantner left Starship in the mid-1980s, complaining that the music had become "mundane," leaving before Slick enjoyed chart success in a third decade with We Built This City and Sara.

Kantner then was part of a group for a time with Balin and former Airplane bassist Jack Cassady, both of whom had left the Jefferson fold years earlier.

The original lineup of Jefferson Airplane would reform for an album in 1989 and were inducted into the Rock and Roll Hall of Fame seven years later. The band will receive a Grammy lifetime achievement award at next month's Grammy Awards ceremony.

Kantner and Slick were in a relationship for a number of years, with a daughter, China, born in 1971. Kanter was also father to two sons, according to the Chronicle.

With files from Reuters and The Associated Press