An American musician considered one of the foremost bass guitarists of the rock era.

Growing up in Washington DC, Casady started playing guitar at the age of 12 and developed an ealy love of the blues. He met up with Jorma Kaukonen, who lived locally and was a few years older, with whom he began to play. By 1959, they had formed a band called The Triumphs, with Casady on lead guitar, Kaukonen on rhythm guitar and vocals, Ronnie McDonald on drums and Warren Smith on bass.

Casady switched to bass during his high school years and while still underage (and with a forged ID) started playing the Washington DC club scene, backing artists such as Little Anthony and the Imperials and Ray Charles.

In September 1965, Casady got a call from Kaukonen, who had transferred to university in San Francisco and become immersed in a new music scene developing there. On hearing that Casady was now playing bass, Kaukonen invited him to join Jefferson Airplane, which was just being formed. Casady quit college in October and moved to San Francisco and joined the Airplane, replacing original bassist Bob Harvey. Here his musical career began in earnest and he became renowned for the inventive, melodic bass lines he contributed during his 7-year tenure with the band.

Casady's appetite for playing led him to do extensive moonlighting during his Airplane tenure. Not only did he perform live on stage with Jimi Hendrix during 1968, he also played bass on Voodoo Chile on the Electric Ladyland album released in the same year. He also occasionally played with other key San Francisco bands including the Grateful Dead and Country Joe and the Fish. Furthermore, he was a member of two short-lived splinter groups, Mickey and the Heartbeats (with Jerry Garcia and Mickey Hart) and Jack Casady and the Degenerates, although neither of these groups ever recorded.

Later, Casady appeared on David Crosby's If I Could Only Remember My Name (1971) and Warren Zevon's Transverse City (1989) and produced Kaukonen's first solo album, the critically acclaimed Quah in 1974.

Casady and Kaukonen formed Hot Tuna in 1969, and they still perform to the present day. The group has morphed over the years from an acoustic blues unit to an electric boogie band to a rampaging metal act and back again.

In the late 1970s, Casady and Kaukonen found that they needed some creative time apart and Hot Tuna disbanded for several years. During this time, Casady helped found a short-lived new wave rock band, SVT, with Brian Marnell. Also during the 1980s, Casady joined former Airplane members Paul Kantner and Marty Balin in the KBC Band.

Not a singer and never a prolific songwriter, it was not until June 2003 that Casady released his first solo album, Dream Factor, produced by his wife Diane Quine. It featured substantial support from the likes of Warren Haynes, Doyle Bramhall II, Kaukonen, Ivan Neville and many other musician friends.

Currently, as well as performing with Hot Tuna, Casady teaches bass workshops at Kaukonen's Fur Peace Ranch in Ohio. He is also currently playing in a new group Moonalice alongside former Jefferson Starship bassist and Hot Tuna pianist Pete Sears.