An American rock bass player. For a period of about 25 years, Kahn was Jerry Garcia's principal collaborator outside the Grateful Dead.

Kahn first began his collaborations with Garcia's numerous side projects in May 1970. He played in every line-up of the Jerry Garcia Band and was in many other Garcia side projects, including Reconstruction, that made its public debut in 1979. Kahn was also bassist for Legion of Mary, the legendary incarnation of the Jerry Garcia Band that featured both Garcia and Kahn, as well as Merl Saunders on keyboards and vocals, Martin Fierro on saxophone and flute, and Ron Tutt on drums. Although the lifespan of Legion of Mary was only from January to July 1975, it is noted as one Kahn's finest collaborative efforts with Garcia.

Kahn also was bassist for the Merl Saunders and Jerry Garcia band, which made its debut in May 1973 and continued until the end of 1974. He played acoustic stand-up bass in Old and in the Way, one of the first 'newgrass' groups that toured during 1973. The band, along with Kahn, featured Garcia on banjo and vocals, David Grisman on mandolin and vocals, Peter Rowan on guitar and vocals, and Vassar Clements on fiddle. Kahn also played alongside Garcia as acoustic bassist in the Jerry Garcia Acoustic Band, and often during the early 1980s as the guitarist's only accompanist in the Garcia and Kahn folk duo.

Although Kahn did occasional work for the Grateful Dead, serving as producer/engineer for the band's Egypt '78 live album and contributed organ and additional production to Shakedown Street, according to some Kahn was generally not well liked within the Dead's scene for allegedly encouraging Garcia's drug habit, especially during the 1990s as Garcia's health began to decline.

Prior to his involvement with Garcia, Kahn played with Mike Bloomfield and Al Kooper and was briefly a member of the Paul Butterfield Blues Band in one of its later line-ups. Other collaborators include Maria Muldaur, with whom he briefly had an affair, Nick Gravenites and John Lee Hooker.

Kahn died at his home in Mill Valley, California in May 1996 from complications of heart disease.