Alan Pasqua was born on June 28, 1952, in New Jersey and grew up in Roselle Park, about twenty miles from New York City. His father played bass, and he started on piano as a small child after watching his older brother Michael take lessons. The first live jazz he remembers is Buddy Rich's big band on Atlantic City's Steel Pier, and the record he credits with turning him toward jazz is Miles Davis's Jazz Track, where he first heard Bill Evans and John Coltrane. He was a rock listener at the same time, and as a teenager he rode into the city to see Grand Funk Railroad, Three Dog Night and the Guess Who.

He spent two years at Indiana University before a meeting with Jaki Byard at the New England Conservatory changed his plans. After the two of them played rhythm changes together on two pianos in Byard's studio, Byard suggested he transfer to Boston and study with him. Pasqua took a bachelor's degree in jazz studies at the conservatory, and his teachers over those years also included Thad Jones, George Russell, David Baker and Gunther Schuller.

A concert at Carnegie Hall in 1975 put him in front of the drummer Tony Williams, who asked him to join the New Tony Williams Lifetime, the quartet Williams put together that spring with the bassist Tony Newton and the guitarist Allan Holdsworth. The band made two albums for Columbia, Believe It (1975) and Million Dollar Legs (1976), and Pasqua is credited as a writer on both, including "Proto-Cosmos" on the first. He has said Williams almost never told him what to play. Williams preferred to talk about orchestration: where the gaps in the band's sound were, and how to play a melody with the drummer without simply doubling him. Williams moved on to a new lineup in 1977.

Pasqua moved to Los Angeles, where the engineer Bruce Botnick, who had produced the Lifetime record, introduced him to Eddie Money. He played on Money's early albums, including "Two Tickets to Paradise" and "Baby Hold On," and toured with him for three months. A chance meeting in a hallway at a New York rehearsal studio with the bassist Rob Stoner led to his next job. Stoner was putting together Bob Dylan's 1978 band, and after several days of rehearsals at Rundown Studios in Santa Monica, during which the field of keyboard players thinned out until only Pasqua remained, he was in. The band, which added a saxophonist and backing singers, played a world tour of 114 dates. Pasqua plays on the two albums that came out of it, the live Bob Dylan at Budokan, taken from some of the tour's earliest shows in Tokyo, and Street-Legal, which the band cut live in a rehearsal studio over a few days. The gospel albums Dylan made next did not include him.

Carlos Santana, who had crossed paths with Pasqua while both were on the road, hired him for Santana in 1979. He co-wrote "Aqua Marine," "You Know That I Love You," "Summer Lady" and "Hard Times" for Marathon (1979) and "Tales of Kilimanjaro" and "Hannibal" for Zebop! (1981), the second produced by Keith Olsen. He left the band after objecting to how its members were being treated. Olsen then brought him into the Los Angeles studio world, starting with Pat Benatar's Precious Time and records for Rick Springfield. Session work for Sammy Hagar and Eddie Money's No Control (1982) followed, plus a co-writing credit with Todd Sharp on Christine McVie's "Keeping Secrets." Jazz leaders kept calling as well: he played piano on Sheila Jordan's Confirmation (1975) and Allan Holdsworth's Velvet Darkness (1976), keyboards on Stanley Clarke's Hideaway (1986), and piano on Eddie Daniels's Under the Influence (1993) and John Patitucci's One More Angel (1997). Later rock and pop credits include John Fogerty's Eye of the Zombie (1986), which he toured behind, Starship's No Protection (1987), Bruce Willis's blues album The Return of Bruno (1987), and Allan Holdsworth's Sand (1987).

In 1987 he and the guitarist Dann Huff formed the melodic hard rock band Giant. Their A&M debut Last of the Runaways (1989) contained "I'll See You in My Dreams," which Pasqua wrote with Mark Spiro and which was the band's one hit in 1990. A second album, Time to Burn (Epic, 1992), followed while Pasqua was living in New Mexico, where he spent about five years. Away from the band he co-wrote the theme for the CBS Evening News with John Trivers and Liz Myers, and composed the score for the 1998 Adam Sandler film The Waterboy.

His own jazz recordings mostly date from the mid-1990s. Milagro (Postcards, 1994) features Jack DeJohnette, Dave Holland and Michael Brecker among its players, and Dedications (Postcards, 1995) pairs him with Holland on bass and Paul Motian on drums, with Michael Brecker on tenor saxophone, Randy Brecker on trumpet and Gary Bartz on alto saxophone. After Russian Peasant (1999), he formed a trio with the drummer Peter Erskine and the bassist Dave Carpenter that made Live at Rocco and Badlands on the Fuzzy Music label. His own My New Old Friend (Cryptogramophone, 2005), with Erskine and the bassist Darek Oles, reached No. 15 on the national jazz airplay chart. The trio's Standards (Fuzzy Music, 2007), with Carpenter, was nominated for a Grammy for Best Jazz Instrumental Album at the 51st Grammy Awards in February 2009. In 2006 he reunited with Holdsworth for a tribute quartet to Williams, with Jimmy Haslip on bass and Chad Wackerman on drums, which produced Blues for Tony (MoonJune, 2009). Twin Bill: Two Piano Music of Bill Evans (BFM Jazz, 2011) has him on two pianos playing the music of one of his early heroes. Northern Lights (2017) is a set of his own compositions, and the solo piano records Soliloquy (2018) and Day Dream (2020) are standards played on his own Hamburg Steinway concert grand.

He taught jazz studies at the University of Southern California's Thornton School of Music for 22 years, was named chair of the jazz studies department in 2009, and left at the end of the spring 2023 semester to focus on writing, playing and a private teaching studio. His work for Dylan resumed decades after the 1978 tour. In 2017 he recorded piano music used under Dylan's recorded Nobel Prize lecture, and in 2020 he played piano on "Murder Most Foul," the 17-minute track on Rough and Rowdy Ways, which he recorded in a single day alongside Benmont Tench on organ, with Blake Mills producing. He told Dylan during the session that the free-time piece reminded him of Coltrane's A Love Supreme. The trio's Live in Italy (2022), billed to the Peter Erskine Trio, was nominated for Best Jazz Instrumental Album at the 65th Grammy Awards in February 2023. Pasqua's most recent album under his own name is the solo piano record New Hope (Blue Canoe, April 11, 2025), which mixes his originals with standards by Duke Ellington, Billy Strayhorn, George and Ira Gershwin, Steve Swallow, George Shearing and others.

Pasqua's jazz formation is Bill Evans and Jaki Byard, and Twin Bill is an open homage to Evans, but the habit that kept him working in rock was borrowed from guitarists: he has said he approached pop and rock keyboards as a guitar player would, with rhythm parts ahead of solos. Across Tony Williams's fusion band, Dylan's 1978 tour, Santana and the Los Angeles studio circuit, the principle he describes is to play what is in front of him and respect the composer and the tradition of the music, and it is the same advice he gives students. He also writes, and tells students that every player should, with credits that run from "Proto-Cosmos" and "I'll See You in My Dreams" to a television news theme. As a leader his vocabulary is mainstream and post-bop, in piano trios, two-piano and solo settings, with a fusion side that shows most clearly in his Holdsworth reunion. His rock and pop credits are rock and pop, and they fill most of his career between 1977 and the early 1990s; the jazz side is documented in the Williams and Holdsworth bands, the leader albums, the Erskine trio's Grammy-nominated records and 22 years of teaching jazz studies at USC. DownBeat gave Twin Bill and Northern Lights four stars each, according to his official site.