Graham Nash had been introduced to David Crosby when the Byrds had toured the UK in 1966 and, when the Hollies came to California in 1968, Nash resumed his acquaintance with Crosby. At a party at the home of Cass Elliot, Nash asked Stills and Crosby to repeat their performance of a new song by Stills, You Don't Have To Cry, blending a second harmony on the spot into their singing. The vocals gelled, and the three realised that they had something quite special.

The Hollies, who had enjoyed pop hits in the mid-1960s, had been struggling with the changing music scene in England due to the advent of psychedelia and were planning to do an album of all Dylan covers. Seeing this as a step in the wrong direction, and creatively frustrated with the Hollies, Nash decided to quit and throw his lot in with Crosby and Stills.

Crosby, Stills & Nash became one of the most successful folk-rock acts of the late 1960s and early 1970s. Subsequently expanded to a quartet with the addition of Neil Young, personal tensions between the members caused the group to break up after their tour in the summer of 1970.

All four members achieved significant success with solo albums in the early 1970s. Crosby released If I Could Only Remember My Name, while Nash released Songs for Beginners.

In the autumn of 1971, Crosby and Nash embarked on a successful acoustic tour accompanied only by their own guitars and piano, captured for the 1998 document Another Stoney Evening. On tour, they rediscovered the joy they had felt with CSN at first, minus the egotistic in-fighting that had made the last CSNY shows so difficult.

In 1972, the two recorded an album together as Graham Nash David Crosby. Further work together was precluded by the attempts at reuniting CSNY in 1973 and 1974, but these quickly broke down. Reaching an impasse with the parent band, Crosby and Nash decided to re-activate their duo act, signing to ABC Records and touring regularly.

They ended up releasing three albums for ABC: Wind on the Water (1975), Whistling Down the Wire (1976) and Crosby-Nash Live (1977). All three albums featured a backing band called The Mighty Jitters including Russ Kunkel (drums), Tim Drummond (bass), Craig Doerge (keyboards), Danny Kortchmar (guitar) and David Lindley (guitar/violin). Famed session bassist Leland Sklar alternated with Drummond in the studio. All of these musicians were among the most in demand in Los Angeles at the time, and the line-up of Kunkel, Doerge, Kortchmar and Sklar had previously recorded as The Section. Depending upon availability of the various members, the twosome would either tour as a full blown electric-based aggregation or in a semi-acoustic format with Doerge and Lindley.

In 1979 they reunited to record a new album for Capitol Records, but sessions were dampened by Crosby's increased dependence upon cocaine and the album was eventually released as Nash's Earth & Sky without any songs from Crosby.

The CSN album Live It Up was also supposed to be a Crosby & Nash record, but Atlantic Records refused to release anything that did not feature the full CSN trio.

In 2004, Crosby & Nash released their first studio record since 1976 with the double-album Crosby & Nash. The album featured the duo backed mostly by members of Crosby's solo band CPR.