Despite the early involvement of Judge Smith and Peame, the group found true success as a vehicle for Hammill, whose dark, existentialist lyrics made him the focus of considerable attention. After the release of the 1968 single "People You Were Going To," Judge Smith left Van der Graaf Generator, which by then consisted of Hammill, keyboardist Hugh Banton, bassist Keith Ellis and drummer Guy Evans. The group soon split, and in 1968 Hammill entered the studio, ostensibly to record a solo album; however, he ultimately called in his ex-bandmates for assistance, and when The Aerosol Grey Machine appeared, it did so under the Van der Graaf Generator name.

Although Ellis was replaced by Nic Potter and woodwind player David Jackson, the reconstituted group continued on for 1969's Least We Can Do Is Wave to Each Other. After 1970's H to He, Who Am the Only One, Potter departed; the Generator recorded one more LP, 1971's Pawn Hearts, before Hammill left for a solo career, putting an end to the group. After five solo efforts, however, Hammill again re-formed Van der Graaf Generator in 1975 for Godbluff. Following a pair of 1976 albums, Still Life and World Record, Banton and Jackson exited; as simply Van der Graaf, the band recorded The Quiet Zone with new violinist Graham Smith. After a 1978 live set, Vital, the group officially disbanded, although most members made appearances on Hammill's subsequent solo records.

Twice during the '90s, Van der Graaf reunited for one-off gigs, and in 2005 released a reunion album, Present. Without Jackson, the trio of Hammill, Banton, and Evans recorded Trisector, which appeared in 2008. They appeared in concert frequently during 2009, and released another studio album, A Grounding in Numbers, in 2011. An album of studio jams and outtakes, titled ALT, followed one year later.