Based in Brooklyn, New York, William Parker is the pre-eminent bassist in modern free jazz. He has released more than 150 titles under his own name, and played on hundreds more as a sideman and collaborator. Parker, who is also a poet, painter, and essayist, co-founded the Improvisers Collective with renowned dancer, choreographer, poet, and life partner Patricia Nicholson. He plays in nearly all of its ad hoc groups and leads their big band, the Little Huey Creative Music Ensemble. An important early document was the 1995 Black Saint offering In Order to Survive. As a bassist, Parker is possessed of a formidable technique. It can be heard as a lead instrument in trios (Painter's Spring), duos (Piercing the Veil), and on dozens of recordings with saxophonist David S. Ware and pianist Matthew Shipp. While leading numerous ensembles, Parker has explored and paid tribute to major artists from the Great Black Music tradition including the albums I Plan to Stay a Believer: The Inside Music of Curtis Mayfield and Essence of Ellington. He has also explored soul-jazz, dance, and spoken word, vocal music, and large-scale works. In 2021 he issued a sprawling ten-disc box of unreleased material titled Migration of Silence Into and Out of the Tone World. In 2022, with Andrew Cyrille and Enrico Rava, he issued the tribute offering 2 Blues for Cecil. October's Universal Tonality documented a 2002 performance by a Parker-led band of 17.

Parker grew up in New York City. Very early in his career he formed an association with Cecil Taylor; he played Carnegie Hall with the pianist in the early '70s. Parker released his first album as a leader in 1979. Through the Acceptance of the Mystery Peace (on Parker's own Centering Records) featured saxophonists Charles Brackeen and Jemeel Moondoc, and violinist Billy Bang. Parker became Taylor's regular bassist in the '80s. He played on several of the pianist's European records, and on Taylor's 1989 domestic major-label release In Florescence on AM. Parker left Taylor in the early '90s and began working more often as a leader. He released a big-band record for his own label, then began releasing a series of CDs for other companies, significantly Black Saint. Beside his activities as a leader and community organizer, Parker would continue to work as a sideman through the mid-'90s; he remained the bassist of choice for downtown free players like David S. Ware, Matthew Shipp, and Rob Brown. The year 2000 was particularly busy for Parker as he recorded three of his own dates, including Painter's Spring and O'Neal's Porch, and appeared on numerous recordings as a sideman. The following year, in the wake of the World Trade Center terrorist attacks, Parker's Little Huey Creative Music Orchestra performed Distillation of Souls, dedicated to its victims, and released the live Raincoat in the River, Vol. 1: ICA Concert. He and drummer Hamid Drake issued the duet offering Piercing the Veil through AUM Fidelity, and his Song Cycle (with vocalists Lisa Sokolov, Ellen Christi, and pianist Yuko Fujiyama) was released by Boxholder. In 2002, Parker appeared on no less than 15 albums, among them Shipp's Nu Bop, Ware's Freedom Suite, and Rob Brown's Round the Bend, as well as four of his own trio and quintet dates. The latter, Raining on the Moon, featured vocalist Leena Conquest; he also released Corn Meal Dance.

In 2003, he toured England with Spring Heel Jack, Evan Parker, Han Bennink, Shipp, and J. Spaceman. The album Live appeared from Thirsty Ear. Parker toured for much of the year, and released several concert recordings, some cut some years earlier. They included Spontaneous with Little Huey Creative Music Orchestra at CBGB from the year before, and Never Too Late But Always Too Early with Drake and Peter Brötzmann, captured in 2001. The William Parker Violin Trio issued Scrapbook, and he appeared on Shipp's Equilibrium and numerous other recordings.

Parker's prolific pace continued unabated. The breadth and depth of his various projects as a leader, collaborator, and sideman proved inexhaustible. In 2005, Thirsty Ear released a duet with Shipp entitled Luc's Lantern (named for the French film director Jean Luc Godard), while Eremite issued Fred Anderson's Blue Winter with Parker and Drake in the rhythm section. The following year saw Parker play on Kidd Jordan's Palm of Soul. He also released a duet recording with Drake entitled Beans, Little Huey Creative Music Orchestra's For Percy Heath, and Requiem by the William Parker Bass Quartet featuring Charles Gayle.

In 2007, Rai Trade released The Inside Songs of Curtis Mayfield while Parker (who'd begun the project in 2001 and evolved it over subsequent years) was performing the music of Fats Waller and Duke Ellington in a dance piece called "On Their Shoulders We're Still Dancing," choreographed by Patricia Nicholson. His own quartet saw the Petit Oiseux album released while Tamarindo, a trio group with Tony Malaby and Nasheet Waits, appeared on a self-titled offering from Clean Feed, and Rogue Art released Alphaville Suite: Music Inspired by the Jean Luc Godard Film by the William Parker Double Quartet. The bassist was named one of the "50 Greatest New York Musicians of All Time" by Time Out New York, received a New York State Music Fund commission for the 2008 long-form work Double Sunrise Over Neptune, and performed at Vision Festival XII in August. The same year, Beyond Quantum with Anthony Braxton and Milford Graves was released by Tzadik, and the archival CT: The Dance Project with Cecil Taylor and Masashi Harada was issued by FMP. Among the Parker-related recordings to appear in 2009 were Farmers by Nature with Gerald Cleaver and Craig Taborn, Washed Away, Live at the Sunside with Drake and Sophia Domancich, Moondoc's complete Muntu Recordings box set, and the David S. Ware Quartet Live in Vilnius.

As the second decade of the new century began, Parker released I Plan to Stay a Believer: The Inside Songs of Curtis Mayfield, an expanded double-disc compilation of recordings from 2001-2010, via AUM Fidelity. The album made many jazz critics' year-end best-of lists. Centering Records released his Organ Quartet's Uncle Joe's Spirit House, and Parker appeared on over a dozen albums. The year 2011 held many highlights, not least among them Centering's three-disc solo bass box Crumbling in the Shadows Is Fraulein Miller's Stale Cake and Conversations from Rogue Art, which featured the bassist's solos and interviews with other musicians. Farmers by Nature also issued their sophomore effort, Out of This World's Distortions. No Business released the archival box set Centering: Unreleased Early Recordings 1976-1987 in 2012, while Altitude, a new recording, appeared from the bassist, Cleaver, and Joe Morris. The double-disc Essence of Ellington (billed to the William Parker Orchestra) was issued by Centering. The critical acclaim for the latter was universal.

In 2013, Parker was the recipient of a Doris Duke Artist Award. His quartet recorded Live in Wroclove, and he led the trio session Tender Exploration. AUM Fidelity released the eight-disc box set Wood Flute Songs: Anthology Live 2006-2012, which showcased his various ensembles. Parker appeared on many archival recordings in 2014 as well as in new trio settings led by James Brandon Lewis (Divine Travels) and Ivo Perelman (Book of Sound). The Farmers by Nature band also issued its third album, Love and Ghosts.

Parker revived Raining on the Moon for 2015's The Great Spirit. AUM Fidelity released the three-disc archival box For Those Who Are, Still. Conversations II: Dialogues Monologues was issued by Rogue Art, and collected duet performances with Jordan interspersed with more artist interview snippets. Live at NHKM, in collaboration with Konstruct, was another of the more than 15 recordings the bassist's name was attached to that year. In spring 2016, Centering brought out Stan's Hat Flapping in the Wind, a series of songs with pianist Cooper-Moore and Sokolov on vocals. In July, Song Sentimentale appeared from Otoroku. It was compiled from three nights of concerts at Cafe Oto by Brötzmann, Parker, and Drake, and released as two separate volumes in different formats. Each contained a unique track listing. The following year Parker was an integral part of two important recording on as many labels: Art of the Improv Trio, Vol. 4 with saxophonist Ivo Perelman and drummer Cleaver on Leo, and Toxic: This Is Beautiful Because We Are Beautiful People with Polish saxophonist Mat Walerian and pianist Matthew Shipp on ESP-Disk. Parker also issued the co-led Bass Duo with Italian classical bassist Stefano Scodanibbio for Aum Fidelity. In 2018, via his Centering label, Parker released the three-disc box set Voices Fall from the Sky, a premier of two long-form works for singers (the title track and "Essence"), as well as a disc of previously issued songs. He followed it with a double disc companion containing the albums Flower in a Stained-Glass Window and The Blinking of the Ear.

A year later, Parker and his oldest flagship group, In Order to Survive, issued the double-length Live/ Shapeshifter, a program cut live in performance at Shapeshifter Lab in Brooklyn, New York. Co-produced by Parker and label boss Steven Joerg, it featured all-new compositions, including the extended suite "Eternal Is the Voice of Love" and "Newark" (dedicated to early group member trombonist Grachan Moncur III), as well as a new iteration of the band's theme. The group comprised original members pianist Cooper Moore and alto saxophonist Rob Brown, as well as drummer Hamid Drake, who joined in 2012. The set was released in June 2019. The following year, Parker, guitarist Nels Cline, and pianist Thollem McDonas recorded the collective jam Gowanus Sessions II for ESP-Disk. He also served as bassist in an improvisational quartet with Daniel Carter, Shipp, and Gerald Cleaver on the 577 Records' album, Welcome Adventure, Vol. 1.

In January 2021, Aum Fidelity released Parker's Migration of Silence Into and Out of the Tone World. The ten-disc box was comprised of completely unreleased instrumental and vocal suites (all for women's voices) composed and recorded between 2018 and early 2020. His music drew inspiration from not only jazz and free improvisation, but musical traditions from Africa, Asia, and European sources. The settings, from solo piano to voice and piano duets to works for chamber strings and full-on orchestral jazz ensembles, paired modern and ancient instruments. Singers on these sessions included Raina Sokolov-Gonzalez, Lisa Sokolov, Ellen Christi, Kyoko Kitamura, and Andrea Wolper. Pianist Eri Yamamoto performed Parker's "Child of Sound" solo.

In September, France's Rogue Art label issued the recording of a 2019 duo concert with Shipp aptly titled Re-Union. In October, the trio of drummer Whit Dickey, Parker and Shipp released Village Mothership on Tao Forms; later that month, ESP-Disk issued the collaborative No Joke by Parker and Patricia Nicholson. January of 2022 saw the TUM release of 2 Blues for Cecil, in collaboration with drummer Andrew Cyrille and trumpeter Enrico Rava, in tribute to Cecil Taylor. In June, the second volume of his collaboration with Carter, Cleaver, and Shipp was released as Welcome Adventure, Vol. 2. That October, Parker released Universal Tonality on AUM Fidelity. Recorded as a one-off at a TriBeCa studio in December 2002, it featured 16 other musicians from various traditions, generations, and cultures, and included Grachan Moncur III, Jerome Cooper, Billy Bang, Dave Burrell, and Daniel Carter. Its six performances were captured on two discs and showcased a free jazz orchestra in the process of "breathing together" for more than two hours. ~ Thom Jurek & Chris Kelsey, Rovi