José James was born in Minneapolis on January 20, 1978, and is of Irish and Panamanian descent. His father, also named José James, was a multi-instrumentalist of Panamanian background. His mother raised him in Duluth and Minneapolis, with a stretch in Seattle, and he took part in the music programs of two Minneapolis high schools before he started performing around town in his late teens. In 2004 he was one of only two men among the semifinalists of the Thelonious Monk International Jazz Vocals Competition, where he paid tribute to his idol Joe Williams. He then moved to New York to study at The New School for Jazz and Contemporary Music, where a fellow student, the trumpeter Takuya Kuroda, became a close friend and a recurring collaborator.

The BBC DJ Gilles Peterson picked him up for his new label, Brownswood Recordings, and James's first records for it were 12-inch singles in 2007, among them a version of John Coltrane's "Equinox." His first album, The Dreamer, came out on Brownswood in January 2008 with Peterson as executive producer. James wrote most of it, and its covers already showed the range he would keep: "Park Bench People," a piece by the hip-hop group Freestyle Fellowship, Rahsaan Roland Kirk's "Spirits Up Above" with Junior Mance on piano, and Bill Lee's "Nola." The Guardian's John Fordham gave it four stars and heard in it a mix of Leon Thomas, the tonal delicacy of Bobby McFerrin and the soul feel of D'Angelo.

The same years put his voice on other people's records. He sang on Jazzanova's Of All the Things (Verve, 2008), on three tracks of Nicola Conte's Rituals (Schema, 2008), on Chico Hamilton's Twelve Tones of Love (2009) and on Basement Jaxx's Scars and Zephyr albums (XL, 2009), and sings on two tracks of the Junior Mance Trio's Live at Café Loup, recorded in New York on June 17, 2007. Blackmagic (Brownswood, 2010), recorded at a New York studio between April 2008 and June 2009, was a late-night record built on beats and grooves, with Flying Lotus and the Detroit producer Moodymann among those who worked on it, and Kuroda playing on it. For All We Know (Impulse!, 2010) went the other way: a duo album of standards, among them "Autumn in New York," "Body and Soul" and "Lush Life," with only the Belgian pianist Jef Neve. It won the Edison Award and the Académie du Jazz Grand Prix as the best vocal jazz album of 2010.

Blue Note released No Beginning No End in January 2013. James produced it with Brian Bender and Pino Palladino, Kuroda wrote the horn arrangements, and the players included the pianists Robert Glasper and Kris Bowers and the drummers Chris Dave and Richard Spaven. It debuted at No. 1 on Billboard's jazz albums chart, and PopMatters described it as a modern soul record that comes out of both hip-hop and jazz. While You Were Sleeping followed in June 2014, co-produced with Bender, Bowers, Spaven, Brad Allen Williams and Solomon Dorsey, and with songs co-written by the singer Taali (Talia Billig), his future wife. The sound drew on rock and R&B, and James has named Nirvana, Radiohead, Frank Ocean and James Blake among the influences on it. In the same period he produced Kuroda's Blue Note debut, Rising Son (2014), and the Japanese singer noon's tenth-anniversary album Full Moon (2013), which was recorded in New York with his band.

The next Blue Note albums were tributes. Yesterday I Had the Blues: The Music of Billie Holiday (2015) marked the centenary of Billie Holiday's birth. It was produced by Don Was, with Eric Harland on drums, John Patitucci on bass and Jason Moran on piano, and it closes with an unaccompanied "Strange Fruit." It won him a 2016 ECHO Jazz award. Love in a Time of Madness (February 24, 2017) turned openly to contemporary R&B, with Antario Holmes as its main producer, and critics split on it: some read it as a deliberate bid for a pop audience, and others as a plain statement of where his taste lay. His version of "They Can't Take That Away from Me" appeared on the Fifty Shades Darker soundtrack that month. Lean On Me (September 28, 2018) covered twelve songs by Bill Withers, produced by Was at Capitol Studios with Palladino, Bowers, Williams and the drummer Nate Smith, and guests including Lalah Hathaway, the saxophonist Marcus Strickland and Kuroda. It began as a medley in his live set, and he has said that Withers approved the idea over dinner.

In 2018 James and Taali founded the independent label Rainbow Blonde Records in New York, with Bender, and the label reissued The Dreamer for its tenth anniversary that year. Its releases from James include No Beginning No End 2 (March 2020), with Lizz Wright as the featured vocalist on "Take Me Home," the live set New York 2020 (February 2021), taken from Levon Helm Studios in Woodstock and Le Poisson Rouge in New York, Merry Christmas from José James (2021), with Aaron Parks on piano and organ, and On & On (January 20, 2023), a set of songs by Erykah Badu with two alto saxophonists. 1978 (April 5, 2024), named for the year of his birth, is the first record since The Dreamer that he produced entirely himself. Marcus Machado on guitar, Chad Selph on keyboards, David Ginyard on bass, Jharis Yokley on drums and Pedrito Martinez on congas carry it, Baloji and Xênia França are guests, and it ends with "For Trayvon" and "38th & Chicago," the second written for his fellow Minneapolitan George Floyd. A follow-up, 1978: Revenge of the Dragon, came out on May 16, 2025, and in August 2025 he was the featured vocalist on "Moanin'" on Christian McBride's big band album Without Further Ado, Vol. 1 (Mack Avenue). He sang on Junko Onishi's Very Special (2017) and was a guest vocalist on Ben Wendel's All One (2023). James married Taali in 2019.

James is a baritone, and his own account of his music is that of a jazz artist for the hip-hop generation. He grew up listening to hip-hop and soul, and has said that John Coltrane and Nat King Cole drew him to jazz. His own biography cites J Dilla and Madlib, Marvin Gaye's I Want You and the songwriter Leon Ware, and Quincy Jones's production on Michael Jackson's Off the Wall, and he has said that Prince's battle with his record label weighed heavily in his and Taali's decision to go independent. The R&B and hip-hop side is not a sideline here. Beats, soul songwriting and a collaborator list that runs from Flying Lotus and Moodymann to Robert Glasper and Aloe Blacc are as much of his catalog as the standards and the tributes, and on Love in a Time of Madness and 1978 it is the main subject. Critics have not settled where to file him, and NPR placed him alongside current R&B innovators such as Frank Ocean and Miguel as readily as beside jazz singers. His jazz side is just as documented: the standards duo with Jef Neve, the Holiday record with Moran, Patitucci and Harland, and the Withers tribute cut with Palladino, Bowers and Smith. The subgenre tags above cover only the jazz and jazz-adjacent categories his work touches, and the hip-hop and R&B side is described here in prose.