Sam Yahel was born in 1971 and raised in Europe, starting piano lessons at six. Press biographies place his birth in Atlanta, Georgia; the English Wikipedia entry gives only "Europe," which is where he grew up rather than where he was born, and the two accounts have never been reconciled in print. He has said that a professional life in music looked like fantasy to him as a teenager, and that a year spent working abroad after high school is what settled the question. He moved to New York City in 1990 and enrolled in the jazz program at the New School, where his classmates included Brad Mehldau.

He arrived as a pianist and left as an organist. The switch happened within months of the move, when a friend who needed to rent a Hammond for a gig invited him along to SIR Studios to help pick one. Yahel sat down at a B-3 and bought a portable organ of his own inside a month. What drew him, by his own account, was the pedal register: the organ let him take over the bass function and lock in with a drummer in a way the piano never had. Early road work with saxophonist Maceo Parker sharpened the point, and Yahel has described Parker's concentration and control of groove as the thing that shocked him into taking rhythm seriously. His first documented recording is the Rick Stone Quartet's Steppin' Back (Jazzand, September 1994), an organ-quartet date with Eric Alexander on tenor.

By the mid-1990s he was the organ player New York's straight-ahead scene called. His leader debut, Searchin', was cut live to two-track digital at Sony Music Studios on April 20, 1996 and issued by Naxos Jazz in 1997, with Peter Bernstein on guitar, Joe Strasser on drums and Ryan Kisor and Eric Alexander added on four tracks. Bernstein became his longest-running partner: the two are together on Searchin', on Yahel's Criss Cross date Trio (recorded December 8, 1997 with Brian Blade), on In the Blink of an Eye (recorded April 18, 1999 at Nola Studios), and across most of a decade of Criss Cross sideman sessions, among them Kisor's Battle Cry (1997), Ralph Bowen's Soul Proprietor (2001), Wycliffe Gordon's Dig This! (recorded December 2002), Jim Rotondi's New Vistas (recorded November 2003, with Chris Potter on tenor) and Bowen's Five (2007). Kisor's Donna Lee, recorded at Chung King Studio on November 25, 2003, put Yahel and Bernstein alongside drummer Gregory Hutchinson.

The band that changed his career formed at Smalls in the late 1990s, when Yahel hired saxophonist Joshua Redman and drummer Brian Blade for a trio of his own. The chemistry outgrew the club: the three recorded at Sear Sound in January 2002 and released the album as Yaya3 on Loma in June of that year, then reconvened at the same studio that March under Redman's name for Elastic (Warner Bros., September 10, 2002). Elastic was Redman's first electric record after eight acoustic albums, and Yahel covered it almost single-handedly, playing Hammond B-3, Fender Rhodes, Wurlitzer, clavinet, grand piano and two synthesizers, taking an additional-production credit, and writing the one track on the album that is not Redman's, "Oumou," named for the Malian singer Oumou Sangaré. He returned as co-producer, arranger and keyboardist on the Joshua Redman Elastic Band's Momentum (Nonesuch, May 24, 2005), contributed to four of its compositions, and shared in its Grammy nomination for Best Contemporary Jazz Album at the 48th Annual Grammy Awards. The same trio recorded once more under Yahel's name as Truth and Beauty, cut at LoHo Studios in September 2005 and released by Origin in June 2007 with liner notes by Brad Mehldau; Yahel took its title from Keats.

Alongside the Elastic work he built an unusually wide accompanist's résumé. He plays Hammond B-3 on three tracks of Norah Jones's Come Away with Me (Blue Note, 2002), the album that swept the 2003 Grammys. He is on nine of the twelve tracks of Madeleine Peyroux's Half the Perfect World (Rounder, September 2006), moving between Hammond, Estey organ, Wurlitzer and acoustic piano, and on the opening track of Lizz Wright's Salt (Verve, 2003). He toured in a Bill Frisell trio with Blade, documented on the download-only Jazz Standard New York City, NY May 1st, 2004 Set 3 (Songline/Tone Field Productions). He recorded two audiophile projects for Chesky: Mysterious Shorter (April 19, 2006), a quintet reading of Wayne Shorter compositions with Nicholas Payton, Bob Belden, John Hart and Billy Drummond, and Jazz Side of the Moon (recorded at St. Peter's Episcopal Church on September 11 and 12, 2007), an instrumental reworking of Pink Floyd's The Dark Side of the Moon with Seamus Blake, Mike Moreno and Ari Hoenig, which Yahel co-produced. On March 31, 2009 Posi-Tone issued guitarist Yotam Silberstein's Next Page, with Yahel on organ, Chris Cheek on tenor and Willie Jones III on drums.

Three weeks later the same label released Hometown, and it was not an organ record at all. Recorded at Acoustic Recording in Brooklyn on October 22, 2007 with Matt Penman on bass and Jochen Rueckert on drums, it was Yahel's first album as an acoustic pianist, and the trio carried forward to From Sun to Sun (Origin, August 2011), where he moved between piano and Hammond across a single program for the first time. His organ trio spent part of this period touring the world as an opening act for Steely Dan, an invitation his label credits directly to Donald Fagen and Walter Becker. Sideman work continued through the 2010s: Toine Thys's The Optimist (Igloo, 2019), Tia Fuller's Diamond Cut (Mack Avenue, 2018), Massimo Biolcati's Incontre (Sounderscore, recorded September 2019 with Dayna Stephens), and an organ credit on Jon Batiste's We Are (Verve, 2021), which took Album of the Year at the 64th Annual Grammy Awards. Fourteen years after From Sun to Sun, he returned as a leader with Quiet Flow (La Reserve, December 5, 2025), a trio with Larry Grenadier on bass and Brian Blade on drums that again splits its ten tracks, eight of them Yahel originals, between Hammond B-3 and piano.

Yahel plays the B-3 against its own reputation. The instrument's canonical voice in jazz, built by Jimmy Smith, Jack McDuff, Shirley Scott and Don Patterson, is a loud, blues-saturated, front-of-house sound, and Yahel has said plainly that the organ is capable of far more subtlety than that tradition usually asks of it. In practice that means constant drawbar adjustment rather than a fixed registration, voice-leading he traces to classical study, and a habit of pulling the low-mid frequencies almost entirely out of his sound when a bassist is present so that the two are not fighting for the same register. Mehldau, writing the liner notes to Truth and Beauty, located Yahel in a generation of players who move between idioms without treating any one of them as the default. Critics have heard the electric groups the same way: AllMusic's review of Momentum set Yahel's keyboards against Miles Davis, Herbie Hancock and Eddie Harris rather than against the organ-combo lineage. The unusual thing about his later work is that he is a genuine two-instrument player rather than an organist who also owns a piano, and Hometown, From Sun to Sun and Quiet Flow are the records where he works out what the two have to do with each other. He has placed at the top of DownBeat's International Critics Poll in the Talent Deserving Wider Recognition category on the organ.