Brian Auger was born on July 18, 1939, in Hammersmith, West London. His father owned a Kastner pianola, and from about the age of four he pumped its pedals and watched the keys move, which is how he first worked out the keyboard. His family's house was bombed in the war and he was evacuated with his sister to a household just south of Leeds for about two years, where a piano in the house let him pick out tunes he heard on the radio. He never took lessons. His older brother brought home jazz records on 78, including Duke Ellington, Louis Armstrong and Kid Ory, and at about ten he found the American Forces Network jazz hour on a radio he had rigged with an aerial out of the bedroom window. Oscar Peterson's "Tenderly" was the record that made him want to play, and school friends who knew the Jazz Messengers pointed him to Horace Silver, whose tunes he learned.

His first professional jobs came through the Soho club scene. Tenor saxophonist Jimmy Skidmore, father of saxophonist Alan Skidmore, called him for a Flamingo Club gig, and he also worked in vibraphonist Dave Morse's quintet; Freestyle Records later listed Tommy Whittle, Dick Morrissey and Tubby Hayes among the British saxophonists he played with in those years. He then ran his own piano trio at the Flamingo with Rick Laird on bass and Phil Kinorra on drums, opening for visiting bands and sharing bills with Tubby Hayes and Ronnie Scott. Laird played in his early Trinity from July 1963 and in the Brian Auger Group of 1964, which included a young guitarist named John McLaughlin; Laird later became a founding member of McLaughlin's Mahavishnu Orchestra. Auger and McLaughlin took whatever work was available, mostly weekend sets on American air force and army bases, and by Auger's account no recording of that band was made because British labels doubted that British jazz would sell.

The organ arrived by accident. Auger heard Jimmy Smith's Back at the Chicken Shack in a Shepherd's Bush record shop and could not place the sound. Rik Gunnell, who ran the Flamingo all-nighters, kept telling him to get an organ because every band he booked had one. When Georgie Fame fell ill with sunstroke, Gunnell sent Auger to cover a run of dates, the first at the Roaring 20s on Carnaby Street, on Fame's own Hammond. He told a curious musician afterward that he had been playing the organ for about 45 minutes. He bought a Hammond L, then a B-3 after seeing a picture of one on a Jimmy McGriff album, and moved from pianist to organist for good. Auger describes himself in those years as a jazz snob, and says the jamming and session work of the mid-1960s, including a harpsichord part on the Yardbirds' "For Your Love" in 1965, changed his mind about rock and blues.

In 1965 he formed the Steampacket with Long John Baldry, Julie Driscoll, Vic Briggs and Rod Stewart. Contractual trouble kept the band from making official records, though nine promotional tracks were cut in late 1965 and issued in France in 1970. When it ended, Auger built a new Trinity around Driscoll, recording for Giorgio Gomelsky's Marmalade label: Open (1967) and Definitely What! (1968), then the double album Streetnoise (1969). Driscoll's version of Bob Dylan's "This Wheel's on Fire" reached No. 5 on the UK singles chart in June 1968 and No. 13 in Canada, and Open reached No. 12 on the UK albums chart. Streetnoise reached No. 41 on Billboard's album chart and mixed Auger originals with covers of Miles Davis's "All Blues," Nina Simone's "Take Me to the Water," Laura Nyro's "Save the Country," the Doors' "Light My Fire" and Richie Havens's "Indian Rope Man." The group toured the United States, opened for Led Zeppelin at the Rose Palace in Pasadena on May 2 and 3, 1969, and appeared with the Monkees on the NBC special 33 1/3 Revolutions Per Monkee. Both "Save Me" and "This Wheel's on Fire" also did well in Italy, a country he kept returning to and where he met his wife, Ella, at a Milan club in 1967; they married in London in 1968.

Driscoll left after Streetnoise, and the Trinity continued as a quartet with Gary Boyle on guitar, Dave Ambrose on bass and Clive Thacker on drums. Their RCA Victor album Befour (1970) reached No. 184 on Billboard and includes Herbie Hancock's "Maiden Voyage" and Eddie Harris's "Listen Here." In 1970, shortly after leaving the short-lived Wassenaar Arrangement jazz-rock commune near The Hague, Auger formed Brian Auger's Oblivion Express, a name he chose half in jest because he expected a band that mixed jazz with rock to be the quickest route to oblivion. The first lineup was Auger on keyboards and lead vocals, Jim Mullen on guitar, Barry Dean on bass and Robbie McIntosh on drums, and the debut album (RCA Victor SF 8170) opens with McLaughlin's "Dragon Song," which McLaughlin had played him in a New York studio. As a songwriter he had three pieces, "On Thinking It Over," "Tomorrow City" and "Trouble," recorded by Sarah Vaughan on A Time in My Life (Mainstream, 1971). Auger produced the 1971 album by Mogul Thrash, whose members Roger Ball and Malcolm Duncan later helped found the Average White Band, as McIntosh and Steve Ferrone, two Oblivion Express drummers, also did. The Express made A Better Land (1971), Second Wind (1972, No. 170 on Billboard), Closer to It! (1973), Straight Ahead (1974), the two-volume Live Oblivion (1974 and 1976) and Reinforcements (1975) for RCA Victor, with Alex Ligertwood on vocals in the middle years, and Happiness Heartaches (1977) for Warner Bros. By January 1976 he was writing liner notes from California.

Later work moved between rock, soul and jazz without settling. He reunited with Driscoll, by then Julie Tippetts, for Encore (1978), and on July 27, 1978, he played keyboards in Tokyo with the Tony Williams All Stars, a band that also had Ronnie Montrose, Mario Cipollina and Billy Cobham. In the mid-1980s he toured with Kim Simmonds, Gregg Errico and Tim Bogert as Maestro, played on the Italian singer Mango's Odissea (1986), served as musical director of the German television series Villa Fantastica (1989), and toured and recorded the live album Access All Areas (1993) with Eric Burdon. From 2000 he joined the trio CAB as a guest and then a billed member alongside Dennis Chambers, Tony MacAlpine and Bunny Brunel, and CAB 2 was nominated for the Grammy for Best Contemporary Jazz Album at the 44th Annual Grammy Awards. Oblivion Express was revived in 2005 with his son Karma Auger on drums and daughter Savannah Auger on vocals. He made Language of the Heart (2012) with Jeff "Skunk" Baxter and Julian Coryell as guests, Train Keeps A-Rolling (2013) with Jeff Golub, and toured Japan and Europe in 2014. In 2018 Freestyle Records issued Full Circle: Live at Bogie's, which the label presented as his first jazz piano album, recorded with his piano trio at a venue that gave a different trio a night for a week. In 2022 the Soul Bank label issued the compilation Auger Incorporated and a five-LP Trinity box set, Far Horizons, followed in 2023 by the six-disc Complete Oblivion, and Strut reissued Oblivion Express albums in 2026, including Reinforcements in June. In 2022 he was living in Los Angeles, and a documentary about his career, I Speak Music, was reported in March 2025 to be in preparation.

Auger came to the Hammond organ as a modern-jazz pianist, and the playing keeps that background. The harmonic vocabulary comes from the pianists he admired, Horace Silver and the keyboard players in Miles Davis's groups, and the attack comes from Jimmy Smith, over a rhythm section that leans on rock and soul grooves. His own account of the Oblivion Express project is that he wanted to build a bridge between the rock and jazz scenes and lead people wherever they wanted to go, laying jazz harmony and improvisation over a funk rhythm section and a soul singer, an approach he was taking before "fusion" had become a category. He quotes Duke Ellington's line that there are only two kinds of music, good and bad, as the reason he kept changing direction. Jazz repertoire runs through both of his main bands, from Miles Davis's "All Blues" and Herbie Hancock's "Maiden Voyage" to Eddie Harris's "Listen Here" and John McLaughlin's "Dragon Song."

The rock, soul and pop sides of his career are large, and they are stated here plainly. The Steampacket, the Yardbirds session and the Driscoll hit single made him a name in British rock and pop in the 1960s, the Trinity and Oblivion Express played to rock audiences across Europe and the United States, and he is generally described as a jazz-rock and rock keyboardist. The jazz side rests on his Flamingo Club apprenticeship, the jazz repertoire on albums from Streetnoise onward, his Tokyo date with the Tony Williams All Stars, his work in CAB, and a 2002 Grammy nomination in a jazz category. In the late 1980s a new generation of British clubgoers rediscovered his early-1970s records and he began to be called the godfather of acid jazz. He says Eddie Piller, who founded the Acid Jazz label, told him that Closer to It! had been the template for the label, and the Brand New Heavies and the James Taylor Quartet cited him. Hip-hop producers also borrowed from him; Yasiin Bey (Mos Def) built "If You Can Huh! You Can Hear" on the Oblivion Express live version of "Maiden Voyage."