Wilber Morris was born November 27, 1937, in Los Angeles, California, the older brother of cornetist and conductor Lawrence "Butch" Morris. He started out on drums as a child, then enlisted in the U.S. Air Force in 1954; during his eight years of service he switched to double bass. Off duty he played around San Francisco alongside a young Pharoah Sanders and saxophonist Sonny Simmons, and after his discharge in 1962 he returned to Los Angeles and worked with alto saxophonist Arthur Blythe and pianist/bandleader Horace Tapscott, playing in Tapscott's Pan-Afrikan Peoples Arkestra. He moved back to San Francisco in 1969, but his career as a jazz musician did not take off in earnest until he relocated to New York in 1978.

In New York, Morris quickly found work with violinist Billy Bang and, within months of arriving, played bass on his younger brother Butch Morris's debut as a leader, In Touch... But Out of Reach, recorded in concert December 22-23, 1978 and released in 1982 on the Kharma label. He also began what would become his longest-running association, with saxophonist David Murray: Morris was the bassist on Murray's octet debut, Ming (1980, Black Saint), and stayed in that chair through Home (1982), Murray's Steps (1983), New Life (1987), and Hope Scope (1991). In July 1981 he recorded his first date under his own name, a trio session with alto/baritone saxophonist Charles Tyler and drummer Denis "Jazz" Charles cut at Air Studio in New York, though it would not surface commercially for thirteen years, released in 1994 as Collective Improvisations on the French label Bleu Regard. That same year he formed his working trio Wilber Force with Charles on drums; its self-titled debut, recorded live February 6, 1983 at Kwame in New York with Murray replacing Tyler on tenor sax and bass clarinet, appeared in 1984 on the Japanese DIW label.

Through the 1980s Morris kept up an extensive sideman schedule alongside his Murray octet tenure, recording repeatedly with Billy Bang (Rainbow Gladiator, 1981; Invitation, 1982; Outline No. 12, 1982) and saxophonist Frank Lowe (Skizoke, 1981; Exotic Heartbreak, 1982), and appearing on Arthur Blythe's Elaborations (1982). In September 1988 he joined Murray, pianist Dave Burrell, and drummer Victor Lewis for the cooperatively billed quartet album Lucky Four (Enja), contributing four compositions of his own, including "Chazz (For Charles Mingus)."

The 1990s brought Morris into drummer Rashied Ali's orbit, and the two built one of the more consistent late-career partnerships of Morris's discography. He played bass alongside Ali on David Murray's studio quartet album Body and Soul (recorded February 1993, Black Saint), then joined Ali, pianist Borah Bergman, and saxophonist Joe McPhee for a quartet set recorded live October 22, 1994 at the Fez Room under Manhattan's Time Cafe, issued in 1996 as The October Revolution (Evidence). Morris also became a member of Ali's Prima Materia, the collective Ali formed to perform the late repertoire of John Coltrane and Albert Ayler. Elsewhere in the decade he co-founded the BMN Trio with German saxophonist Thomas Borgmann (working at various points with drummers Denis Charles and Reggie Nicholson, on albums including Organic, 1997, and ...You See What We're Sayin'?, 1999), recorded a duo album with drummer Reggie Nicholson, Drum String Thing (2000, CIMP, on which he also sang), and joined saxophonist Charles Gayle's quartet for Testaments (1995) and Daily Bread (1998).

Morris and Ali's partnership continued into 2001 with Live at Tonic (DIW), a trio recording with saxophonist Louis Belogenis billed simply as Ali/Belogenis/Morris. One of Morris's final documented performances came on June 4, 2000, also at Tonic in New York: a trio set with pianist Bobby Few and saxophonist Avram Fefer released in 2002, shortly before his death, as Few and Far Between (Boxholder). Wilber Morris passed away August 8, 2002, from cancer, at his home in Livingston, New Jersey, at age 64. Archival material continued to surface posthumously, including Prima Materia's Configurations (The Music of John Coltrane) (2009, featuring Morris's bass on tracks alongside bassist Joe Gallant's on others), the trio session Monks with pianist Borah Bergman and drummer Sunny Murray (2019), and The Spell, a 1987 live trio recording with French horn player Vincent Chancey and drummer Warren Smith (2020).

Morris came up through two distinct scenes before settling in New York: the West Coast avant-garde lineage of Horace Tapscott and the Pan-Afrikan Peoples Arkestra, and the freewheeling improvised-music circuit of 1960s San Francisco. That grounding, combined with his early years on drums, gave him a bassist's time-feel that was as comfortable propelling large-ensemble writing (David Murray's octet charts) as it was disappearing into fully improvised duo and trio settings. He was a favored bass voice for drummers building spare, conversational free-jazz units in the 1990s and 2000s, most notably Rashied Ali, who used him across four separate recorded settings between 1993 and his death, including Ali's own Coltrane/Ayler repertory group Prima Materia. Morris was also a working composer in his own right; his tune "Chazz," a tribute to Charles Mingus, and "Afro-Amerind" (recorded under close variant titles as early as Wilber Force in 1983 and as late as the posthumously issued Spell sessions from 1987) recur across multiple recordings and different bands, suggesting a small, personal repertoire he carried from group to group over two decades.