William D. Evans was born on February 9, 1958, in Clarendon Hills, Illinois. His father was a classical piano prodigy, and Evans began on piano, played clarinet in grade school, and took up saxophone at Hinsdale Central High School. In Chicago he studied with the saxophonists Bunky Green and Joe Daly and, on tenor, with Vince Micko; at the Jazz Showcase he heard Sonny Stitt and Stan Getz in person, and as a young teenager he attended Jamey Aebersold's summer jazz camps. He studied at the University of North Texas and at William Paterson University in New Jersey, where Dave Liebman, an alumnus of Miles Davis's early-1970s bands, was among his teachers. Evans moved to New York in 1979, spent hours playing standards in lofts, and worked with the pianist Hank Jones; their trio album with the bassist Red Mitchell, Moods Unlimited, was recorded in 1982 and issued in Japan.

Liebman recommended his former student when Davis was preparing to return to recording and touring after a long silence, and Davis auditioned and hired him. Evans says he helped assemble the comeback band in 1980, at the age of 22, and that he brought in Mike Stern, Marcus Miller and John Scofield. His recorded debut with Davis was The Man with the Horn (1981), on which he plays soprano saxophone on five tracks. He is also on the live double album We Want Miles (1982), drawn from the band's first concerts, beginning at the Kix club in Boston on June 27, 1981, with Stern, the drummer Al Foster and the percussionist Mino Cinelu, and on Star People (1983) and Decoy (1984), where he plays soprano on two tracks. AllMusic dates his time with Davis from 1981 through the Decoy tour. He is no relation to the pianist Bill Evans, who recorded with Davis in the 1950s.

Alongside the Davis years, Evans recorded with Elements, the fusion group led by the bassist Mark Egan and the drummer Danny Gottlieb, from 1982 to 1990, and played on solo albums by both men. His own debut as a leader, Living in the Crest of a Wave (Elektra Musician), was recorded in November 1983 and released in 1984. He then followed the label's president, Bruce Lundvall, to Blue Note for The Alternative Man (1985), where he also played keyboards and John McLaughlin appeared as a special guest. He was a member of McLaughlin's revamped Mahavishnu Orchestra, appearing on Mahavishnu (1984) and Adventures in Radioland (1986), and toured with Herbie Hancock. In the late 1980s he took part in the all-star Echoes of Ellington sessions with the trumpeter Randy Brecker, the guitarist Robben Ford and the saxophonist Tom Scott.

Summertime (Jazz City, 1989) and two live albums recorded at Blue Note Tokyo, Let the Juice Loose and The Gambler (both 1990), led into the next decade. In 1992 he formed Petite Blonde for a European tour and a live album with the bassist Victor Bailey, the drummer Dennis Chambers, the keyboardist Mitch Forman and the guitarist Chuck Loeb. Push (Lipstick, 1994) set his funk-fusion writing against hip-hop beats and big-band swing, and Live in Europe (1995) followed with the band of that name. For Escapade Music he made Escape (1996) and Starfish & the Moon (1997), and for ESC Records Touch (1999), Soul Insider (2000) and Big Fun (2002), which brought in Les McCann, the guitarist Hiram Bullock and the trombonist Lew Soloff, among others, with John Scofield as a guest on Soul Insider.

Soul Insider and Soulgrass were each nominated for a Grammy Award. Soulgrass (BHM Productions, 2005) fused jazz-funk with bluegrass and Americana, with Béla Fleck, Sam Bush, Bruce Hornsby and the drummer Vinnie Colaiuta among the players. He carried the idea through The Other Side of Something (Intuition, 2007), the first of his albums to feature his lead vocals, Dragonfly (2012) and Soulgrass Live in Moscow (2014), recorded during the first of two U.S. State Department-sponsored tours of Russia. In 2003 he began a long run of touring with the Soul Bop Band, co-led with Brecker, which produced Soul Bop Band Live (2005), and in 2008 he recorded Vans Joint with the WDR Big Band Cologne, arranged and conducted by Michael Abene, with the drummer Dave Weckl and the bassist Mark Egan.

In 2015 he introduced the Bill Evans Band, with the drummer and singer Josh Dion, and began singing on stage. Rise Above (2016) brought in guest vocalists including Gregg Allman and Warren Haynes. He co-led two albums with Ford: The Sun Room (earMUSIC, 2019), with the drummer Keith Carlock and the bassist James Genus, and Common Ground, recorded in Nashville in January 2020 with Carlock and the bassist Darryl Jones and released in 2022. With the drummer Wolfgang Haffner he formed the Spykillers, who toured European festivals in 2019 and issued a live album recorded in Australia. Modern Standards (2023) is a live album with the pianist Niels Lan Doky, Jones and the drummer Harvey Mason, and Who I Am (2024) gathered Fleck, the dobro player Jerry Douglas, the bassist Victor Wooten, John Medeski, Till Brönner and Nils Landgren among its guests. In February 2026 he played eight sold-out shows at Blue Note Tokyo with his Vansband Allstars, a tribute to Davis in the year of the trumpeter's centenary, and that year he also toured with Marcus Miller's We Want Miles band alongside Stern and Cinelu, with the last dates of 2026 in San Francisco from September 24 to 27.

Evans names Sonny Rollins, Joe Henderson, John Coltrane, Stan Getz, Steve Grossman and Dave Liebman as his early saxophone influences. AllMusic describes a taut, lyrical, funky and bluesy tenor tone and a reedy, assertive soprano. His catalogue does not stay in one idiom: it runs from the electric fusion of the Miles Davis years and Elements to the hip-hop-inflected funk of Push, a big-band setting with the WDR, the bluegrass-jazz of the Soulgrass records and the blues-rock of the Robben Ford albums. He has said that Davis told him to write and play what inspires him, and he composes most of his own material, plays keyboards on several of his records, and gives school clinics on jazz improvisation.