Walter Beasley was born on May 24, 1961, and grew up in El Centro, California, in the Imperial Valley near the Mexican border. As a boy he was given a record by Grover Washington Jr., a gift that All About Jazz later credited with starting him on the saxophone. By thirteen he was singing in Spanish with a working band called Los Elegantes, and through middle and high school he played clubs and dances in a string of local groups. He listened to R&B and funk while training on classical and jazz saxophone, a mixture that has defined his records ever since.

He went to the Berklee College of Music in Boston and graduated in 1984, in a class that All About Jazz says included Branford Marsalis and the singer Rachelle Ferrell. A year later he took a short-term teaching job at Berklee that turned into a career. His own biography says he gave the school 35 years, and he now teaches through online classes, instructional DVDs and short lessons on social media. Older profiles still call him a professor there, but that no longer matches his biography, and one profile puts his retirement from the faculty at 2016, so the exact end of the tenure is not settled. The Japanese saxophonist Ami Nakazono, who graduated from Berklee in 2009, names him among her saxophone teachers.

His first album, Walter Beasley, came out on Polydor in 1987, produced by Lionel Job, with Beasley on lead vocals, keyboards, alto and soprano saxophone and flute. Its singles "I'm So Happy" and "On the Edge" reached Billboard's R&B singles chart. Three albums for Mercury followed, Just Kickin' It (1989), Intimacy (1992) and Private Time (1995). A 1996 Houston Press preview of a Houston saxophone bill that also had Gerald Albright, Art Porter and Bobby Watson noted that he played most of the instruments on Private Time and produced it, and that he gave the newcomer Liz Withers room for lead vocals, on a record that ranged from jazz through R&B and funk to hip-hop. Live and More (1996) appeared on his own Affable label.

He moved to Shanachie for Tonight We Love (April 22, 1997), For Your Pleasure (1998), Won't You Let Me Love You (2000) and Rendezvous (2002), and these are the first of his records to reach Billboard's Jazz Albums chart. Go With the Flow (2003), which MusicWeb International reviewed as a disc that leans toward jazz with only a nod to smooth jazz, won the 2003 Boston Music Award for jazz album of the year, two years after the same awards named him outstanding jazz artist. For Heads Up he made For Her (2005), a record with nine producer credits that include Beasley and Chuck Loeb, then Ready for Love (2007) and Free Your Mind (2009). All About Jazz described Ready for Love as part smooth jazz, part R&B, with eight originals, an alto reading of Deniece Williams's "Free," Beasley singing lead, falsetto included, on William DeVaughn's "Be Thankful for What You Got," and a closing tribute, "Willa Mae's Place," to Willa Mae Brothers, who had advised him as a Berklee student. On Free Your Mind the keyboardist James K. Lloyd of Pieces of a Dream wrote and produced five of the eleven songs, and the album includes "DukeZillia," a tribute in part to George Duke, and "Message to Mark," for the late Mark Ledford. "Coolness" (2005), "Ready for Love" (2007) and "Steady as She Goes" (2009) all reached the top two on Billboard's smooth jazz airplay chart, the last two at No. 1.

From 2010 he has largely released his own records on Affable, the label and publishing company he founded and runs, beginning with Backatcha! (2010) and the live sets Live: In the Groove and Live in the Club. I'm Back (2015) took its title track to No. 1 on the airplay chart, and the Blackstreams EP (2017) and Going Home (2019) followed. With the bassist Byron Miller he recorded "The B-Spot" (2019), which reached No. 2, and "Real Love" (2020), a three-way billing with Stevie Wonder. His biography says he stepped back from touring to care for his parents and returned to a nationwide tour in 2023, the year of Do You Want to Dance? (August 22) and "Nice and Easy," a duet with Najee that reached No. 2. He has since put out Live and Blessed and Tribute to Soul (2024), Sin Palabras (2025), his first Spanish-language record, and the 65 Bounce EP (May 26, 2026), whose title track reached No. 2, along with four ambient improvisation albums released on streaming services in July 2026. His website lists tour dates through December 2026.

Beasley plays alto and soprano saxophone and sings, and the singing is not a sideline. His records mix instrumentals with soul vocals, many of them his own, and his repertoire runs through R&B covers, original ballads and uptempo funk more readily than through jazz standards. The label that fits is smooth jazz, made for radio, and he has paired it with R&B for his whole career. The jazz side is real but secondary: a Berklee degree, classical and jazz saxophone training, a few tracks such as "Message to Mark" that stretch toward straight-ahead playing, and a long teaching career. A reviewer for MusicWeb International called him a clear follower of Grover Washington Jr. with an identity of his own, and Washington's soprano and alto sound, rooted in soul and funk, is the obvious lineage. All About Jazz, reviewing Free Your Mind, praised his songwriting and playing while faulting the programmed drums and keyboards that run through much smooth jazz. He has also been a sideman, with soprano and alto parts on Marlena Shaw's Love Is in Flight (1988) and an alto solo on Chuck Loeb's Listen (1999). Beyond the studio he is a known figure in saxophone education, with DVDs on sound production, circular breathing and hip-hop improvisation and several books of advice for musicians.