This first Soft Machine line-up became involved in the early UK underground, featuring prominently at the UFO Club, and subsequently other London clubs like the Speakeasy and Middle Earth, and recorded the group's first single ' Love Makes Sweet Music', as well as some demo sessions that were released several years later. They also played in the Netherlands, Germany and on the French Riviera. During July and August of 1967, the promoter and manager Giorgio Gomelsky booked shows all along the Cote d'Azur with the band's most notorious early gig taking place in the village square of Saint-Tropez. This led to an invitation to perform at producer Eddie Barclay's trendy "Nuit Psychédélique", performing a forty minute rendition of "We Did It Again", singing the refrain over and over, achieving a Zen-like quality. This made them instant darlings of the Parisian "in" crowd, resulting in invitations to appear on leading television shows and at the Paris Biennale in October 1967. Meanwhile, upon their return from their summer sojourn in France, Allen (an Australian) was denied re-entry to the United Kingdom, so the group continued as a trio, while he returned to Paris to found Gong.
Sharing the same management team as Jimi Hendrix, the band were rewarded with a support slot on the Experience's US tours throughout 1968. Soft Machine's first album - a psychedelic rock/proto-prog classic - was recorded in New York in April at the end of the first leg. Back in London, eventual The Police guitarist Andy Summers joined the group, fresh from his stint with Dantalian's Chariot (previously Zoot Money's Big Roll Band). After a few weeks of rehearsals, the new quartet began a tour of the USA with some solo shows before reuniting with Hendrix for a final string of dates in August-September 1968. Summers, however, had in the meantime been fired at the insistence of Ayers. Ayers departed amicably after the final date at the Hollywood Bowl, and for the remainder of 1968 Soft Machine was no more. Wyatt stayed in the US to record solo demos, while Ratledge returned to London and began composing in earnest.
In January 1969, in order to fulfill contractual obligations, Soft Machine reformed with former road manager and composer Hugh Hopper on bass added to Wyatt and Ratledge, and set about recording their second album, Volume Two, which launched a transition towards a purely instrumental sound resembling what would be later called jazz fusion. Notwithstanding the disconcerting personnel changes that came about during this period, this is a fascinating period of creative tension. In mid-1969, this lineup (along with Jerry Shirley of Humble Pie) appeared as the uncredited backup band on Syd Barrett's solo debut album, The Madcap Laughs. The base trio was late in 1969 expanded to a septet with the addition of four horn players, though only saxophonist Elton Dean (†) remained beyond a few months, the resulting Soft Machine quartet (Wyatt, Hopper, Ratledge and Dean) running through Third (1970) and Fourth (1971), with various guests, mostly jazz players (Lyn Dobson, Nick Evans, Mark Charig, Jimmy Hastings, Roy Babbington, Rab Spall). Fourth was the first of their fully instrumental albums, and the last one featuring Wyatt.
All members were highly literate in various musical backgrounds, but foremost was the eclectic genius of Ratledge, who through composition, arrangements and improvisational skills propelled a collective output of the highest standard, in which the vocal charm and extraordinarily original drumming of Wyatt, the lyricism of some of Dean's solos and the unusual avant-garde pop angle of Hopper's pieces all had a major role. Their propensity for building extended suites from regular sized compositions, both live and in the studio (already in the Ayers suite in their first album), reaches its maximum in the 1970 album Third, unusual for its time in each of the four sides featuring one suite. Third was also unusual for remaining in print for more than ten years in the United States, and is the best-selling Soft Machine recording.
This period saw them gaining unprecedented acclaim across Europe, and they made history by becoming the first 'rock band' invited to play at London's elite Proms in August 1970, a show which was broadcast live and later appeared as a live CD.
In 1973, after Six, Hopper left and was replaced by Roy Babbington, another former Nucleus member, who had already contributed with double bass on Fourth and Fifth and took up (6-string) electric bass successfully. This new quartet of Babbington, Jenkins, Marshall and Ratledge recorded the next (and last) three official Soft Machine studio releases. After they released Seven (1973) without additional musicians, the band switched record labels from Columbia to Harvest. On their 1975 album Bundles, a significant musical change occurred with fusion guitarist Allan Holdsworth adding guitar as a very prominent melody instrument to the band's sound, sometimes reminiscent of John McLaughlin's Mahavishnu Orchestra, setting the album apart from previous Soft Machine releases, which had not featured guitars. On the last official studio album Softs (1976), he was replaced by John Etheridge. Ratledge, the last remaining original member of the band, had left during the early stages of recording. Other musicians in the band during the later period were bassists Percy Jones (of Brand X) and Steve Cook , saxophonists Alan Wakeman and Ray Warleigh, and violinist Ric Sanders. Their 1977 performances and record (titled Alive and Well, ironically) were the last for Soft Machine as a working band. The Soft Machine name was used for the 1981 record Land of Cockayne (with Jack Bruce and, again, Allan Holdsworth, plus Ray Warleigh and Dick Morrissey on saxes and John Taylor on electric piano), and for a final series of dates at London's Ronnie Scott's Jazz Club in the summer of 1984, featuring Jenkins and Marshall leading an ad-hoc line-up of Etheridge, Warleigh, pianist Dave MacRae and bassist Paul Carmichael.
Graham Bennett's Soft Machine biography, Soft Machine: Out-Bloody-Rageous, was published in September 2005. In 2006 the book won an Award for Excellence in Historical Recorded Sound Research from the Association for Recorded Sound Collections.