Warren Hill was born in Toronto on April 15, 1966, one of five children. He began on guitar at eight and by his teens was fronting a local rock band, singing Led Zeppelin and Rush. The saxophone came first as a school-band instrument. A summer program at the Eastman School of Music in Rochester, New York, introduced him to jazz, and from there he committed to the horn, taking David Sanborn as his model; his own biography adds Michael Brecker and Charlie Parker to the list of players who changed his direction. He studied physics at the University of Toronto, left to pursue music full time, and enrolled at Berklee College of Music in Boston.

At his Berklee graduation in 1988 he was given several featured solos. Producer Russ Titelman was in the audience and hired him for a session with Chaka Khan. The album was C.K. (Warner Bros., November 22, 1988), where Hill is credited with saxophone on tracks 7 and 8. He moved to Los Angeles, made a demo and signed with RCA. His debut, Kiss Under the Moon (Novus/RCA, June 11, 1991), was co-produced by Hill with Sam Purkin, Michael Boddicker, Preston Glass and Byron De Lear, with Paulinho da Costa on percussion. It reached No. 11 on Billboard's Contemporary Jazz chart, and he went on the road opening for Natalie Cole on her 40-city American "Unforgettable" tour.

The commercial breakthrough came in 1993 with "The Passion Theme," from the film Body of Evidence, written by Graeme Revell and Jeff Silbar, with Hill credited as alto saxophonist and co-producer. AllMusic calls it a chart-topper on the adult contemporary radio format, and the album Devotion (RCA, August 10, 1993) followed, reaching No. 8 on Billboard's Top Jazz Albums and No. 6 on Contemporary Jazz. The same year he played saxophone on country group Restless Heart's "Tell Me What You Dream," which spent two weeks at No. 1 on the adult contemporary chart. Truth (RCA, 1994) matched Devotion at No. 6 on Contemporary Jazz, and radio singles from the era, among them "Our First Dance" and "Do You Feel What I'm Feeling?," made him a fixture of the smooth jazz format.

In 1997 he moved to Discovery Records for Shelter, the first album to feature his own singing; its title song, "Shelter from the Storm," was written and produced with his wife, Tamara VanCleef-Hill. Life Thru Rose Colored Glasses followed in 1998. At Narada he released Love Life (2000), then Love Songs and A Warren Hill Christmas (both 2002). PopJazz (2005), produced with Andre Berry, came out on his own PopJazz label, and La Dolce Vita (Koch, June 24, 2008) produced a title single that reached No. 2 on the Smooth Jazz chart. Later releases include Christmas with Warren Hill (SUGO Music Group, 2012) and Under the Influence, a set of thirteen 1970s rock covers, among them "We Will Rock You," "Walk This Way," "Every Breath You Take" and "Tom Sawyer." His latest confirmed release is the single "Simple," with his daughter, the singer Olivia Rox, issued May 5, 2023 on Songbird Music Group.

Hill has also built a business around the music. He created Warren Hill's Smooth Jazz Cruise in 2004 and sold his interest in 2007, then began producing hotel-based destination events in 2009, including Jammin' in Jamaica (2009) and a Saxophone Summit in Los Angeles (2011). He owns and hosts the Cancun Jazz Festival, which was in its fifth year in 2019, and launched a Los Cabos Jazz Festival that year, held April 25 to 28, 2019 at the Hard Rock Hotel Los Cabos. With Tamara VanCleef-Hill he co-founded the Songbird label, and he sells signature alto mouthpieces. His own biography says he has toured in more than 25 countries and remains especially popular in China and South Korea, where rock covers such as "Hey Jude," "We Are the Champions" and "I Want to Know What Love Is" are a staple.

Hill is a melody-first alto and soprano saxophonist. His records are built around a strong hook, a singing alto line and a radio-length arrangement, and he is filed under adult contemporary and instrumental pop as readily as under jazz: AllMusic lists his genres as Jazz, Easy Listening and Pop/Rock, and his styles as Smooth Jazz, Contemporary Jazz, Crossover Jazz and Jazz-Pop. The pop side is plain in the catalogue, from a film theme and a run of romantic ballads to the 1970s rock covers of Under the Influence, and it traces back to his start as a teenage rock singer and guitarist. The jazz side is the training and the vocabulary: the Eastman summer program, Berklee, and the Sanborn, Brecker and Parker records he names as his first models. His own shop describes the blue rubber mouthpiece he has played for more than thirty years as the secret of his sound. His reputation rests on chart performance: five albums on Billboard's Contemporary Jazz chart between 1991 and 1998 and a string of smooth jazz radio number ones.