David Bryan Benoit was born on August 18, 1953, in Bakersfield, California. He began piano lessons at thirteen with Marya Cressy Wright and went on to study with Abraham Fraser, who had been Arturo Toscanini's pianist. After Mira Costa High School he studied theory, composition and orchestration at El Camino College (orchestration with Donald Nelligan) and took film-scoring classes taught by Donald Ray at UCLA. His conducting training came from Heiichiro Ohyama, an assistant conductor of the Los Angeles Philharmonic, Jan Robertson of UCLA, and Jeffrey Schindler, music director of the UC Santa Barbara symphony orchestra.

He started as an accompanist and music director. In 1976 he became musical director and conductor for the singer Lainie Kazan, and he held similar posts with Ann-Margret and Connie Stevens. AllMusic notes that by the mid-1970s he was also playing on the soundtrack of Robert Altman's film Nashville and accompanying the singer Gloria Lynne, and he appears on drummer Alphonse Mouzon's Blue Note album The Man Incognito (1976). His own debut, Heavier Than Yesterday (1977), came out on AVI Records, and a run of AVI albums followed through the early 1980s, among them Can You Imagine (1980), Stages (1982), Digits (1983) and the holiday set Christmastime (1983). AllMusic describes these records as funk-, disco- and fusion-leaning, pointing toward the crossover sound he later settled into.

The break came in the mid-1980s. This Side Up (1985, Spindletop) was recorded live in the studio with no mixing or overdubs and reached No. 4 on Billboard's jazz albums chart; its version of Vince Guaraldi's "Linus and Lucy," recorded in 1985, got wide radio play and is credited with helping launch the smooth jazz format. In 1986 he also played on the debut album of the Rippingtons, Moonlighting, a group founded by guitarist Russ Freeman. Signed to GRP Records, he made Freedom at Midnight (1987), which reached No. 5 on Billboard's contemporary jazz chart, and Every Step of the Way (1988), which earned a 1989 Grammy nomination for best contemporary jazz performance. Waiting for Spring (1989) reached No. 1 on Billboard's jazz albums chart, Shadows (1991) No. 2 on the contemporary jazz chart, and Letter to Evan (1992), a tribute to Bill Evans, No. 3 on the jazz chart. He also played in the GRP All-Star Big Band, which received a 1996 Grammy nomination for best large jazz ensemble performance, and in 1994 he made The Benoit/Freeman Project with Freeman, which reached No. 2 on Billboard's jazz chart.

Through the 1990s he built a second career as a screen composer and conductor. His score for The Stars Fell on Henrietta (1995), a film produced by Clint Eastwood and starring Robert Duvall, was issued as an album, and he wrote the music for Disney's television film The Christmas Tree, directed by Sally Field. For more than ten years he composed music for the Peanuts television specials, following the example of Guaraldi, whom he names as an inspiration. After the death of Peanuts creator Charles M. Schulz he made Here's to You, Charlie Brown: 50 Great Years! (2000), a tribute album with Take 6, guitarist Marc Antoine and trumpeter Chris Botti. Professional Dreamer (1999) produced "Dad's Room," which was nominated for a Grammy for best instrumental composition. American Landscape (1997) and Orchestral Stories (2005), the latter containing his first piano concerto, "The Centaur and the Sphinx," and the symphonic piece "Kobe," showed the orchestral side of his writing. He conducts as well as plays, with ensembles including the Los Angeles Philharmonic, the San Francisco Symphony and the London Symphony according to his own biography, and he has been music director and conductor of the Asia America Symphony Orchestra; in 2008 he conducted Beethoven's Ninth Symphony with that orchestra and a 200-voice chorus at Walt Disney Concert Hall.

His recording life continued on Concord's Peak label and then Heads Up: The Benoit/Freeman Project 2 (2004), Full Circle (2006), Heroes (2008), the Peanuts retrospective Jazz for Peanuts (2008), Earthglow (2010) and Conversation (2012). In May 2011 he began hosting a morning program on the Los Angeles jazz station KKJZ, whose website still lists him among its on-air staff. In 2015 he released 2 in Love, an all-original vocal album featuring the singer Jane Monheit with lyrics by Lorraine Feather, Mark Winkler and Spencer Day, and the Christmas album Believe; he also played on the soundtrack of The Peanuts Movie (2015). He then recorded So Nice! (2017) with Marc Antoine, the solo piano album The Steinway Sessions (2017), and David Benoit and Friends (2019), with guests including Dave Koz, Peter White and Marc Antoine.

His recent work has leaned toward big band and orchestra. A Midnight Rendezvous (2022) was, according to AllMusic, his first big-band recording under his own name, and Timeless (2024) is a big-band album with the London-based Spice Fusion band. Steinway After Dark, a solo piano album of ballads, followed on May 2, 2025, and on January 30, 2026, he and keyboardist Jeff Lorber released the single "Boarding Pass," which reached No. 1 on the smooth jazz airplay chart. His website lists a cello concerto, Resonance & Renewal, written for the cellist Cecilia Tsan, whose world premiere at Soka University in Aliso Viejo, California, was scheduled for September 26, 2026. Benoit is alive and still working as of November 1, 2026.

Benoit plays in a measured, lyrical style built on clear melody and orchestral color, and AllMusic ranks him among the architects of the contemporary jazz sound and the crossover movement that grew out of the late-1970s fusion era. AllMusic hears the influence of Dave Brubeck, Bill Evans and Vince Guaraldi in his playing, and he has named Guaraldi, Evans and Leonard Bernstein among his chief influences; he paid homage to Evans on Letter to Evan and to Guaraldi on Here's to You, Charlie Brown, and Heroes (2008) covers songs by Elton John, the Beatles and Brubeck, among others. Most of his records are small-group dates with a pop and R&B pulse, which is why radio and the charts file much of his work under smooth jazz, but he also writes for strings and big band, scores films, and conducts. AllMusic lists his genre as jazz, with styles that include contemporary jazz, crossover jazz, piano jazz, smooth jazz and jazz-pop, and its 4.5-star rating of his 1994 record with Russ Freeman is the highest it has given him.