Jason Tiemann is a New York City-based jazz drummer, composer and educator who built his early reputation in the Midwest before establishing himself on the New York scene. His late-1990s credits place him within Lexington, Kentucky's jazz-education circle: he recorded on the University of Kentucky-anchored Dimartino/Osland Jazz Orchestra's Off the Charts (2000, Sea Breeze Jazz) and the Kentucky Jazz Repertory Orchestra's Ellington Celebration (1999, Sea Breeze Jazz), directed by saxophonist Miles Osland and Dick Domek, and continued to record with the related Osland Saxophone Quartet into the 2000s. He has been an artist/clinician for the Jamey Aebersold Summer Jazz Workshops since 1998.

Tiemann's first significant leader credit came from a working trio with German-based American bassist John Goldsby, longtime member of the WDR Big Band Cologne, and alto saxophonist Jacob Duncan. Billed as a genuine three-way co-led group ("Jacob Duncan, John Goldsby, Jason Tiemann" on the Discogs release), the trio recorded Live at the Nachbar (2008, Bass Lion), taped live in Germany on February 27, 2008, and the studio follow-up The Innkeeper's Gun (2010, Bass Lion).

Before relocating to New York, Tiemann spent 12 years on the faculty of the University of Louisville as a professor of jazz drums and percussion, a tenure documented in the school's own concert programs from the period. Once in New York he built a busy freelance career, recording through the 2010s and 2020s largely on the Posi-Tone, Cellar Live and SteepleChase labels with a circle of mainstream and hard-bop-rooted leaders: pianist Andy LaVerne (six SteepleChase albums between 2016 and 2025, including Genesis, Faith, Shangri-La, Rhapsody, Spot On and Crystal Night), vibraphonist Behn Gillece, saxophonist Ken Fowser, trombonist Michael Dease, saxophonist Diego Rivera, trumpeter Josh Lawrence, pianist Ben Paterson, tenor saxophonist Stephen Riley, baritone saxophonists Ronnie Cuber and Gary Smulyan, bassist Neal Miner, and flutist Andrea Brachfeld, on whose If Not Now, When? (2018), Brazilian Whispers (2020) and Evolution (2022, with her group Insight) he plays drums. He also served as co-producer as well as drummer on saxophonist Steve Slagle's Alive in Harlem (2020, Panorama Records).

Tiemann made his own recorded debut as a bandleader with T-Man (2020, T-Man Records), an organ-trio session pairing him with guitarist Ed Cherry, a longtime member of Dizzy Gillespie's band, and Hammond B-3 organist Kyle Koehler. The eleven-track album, five of its compositions Tiemann's own, was released February 11, 2020, was named a DownBeat editors' pick that March, and reached No. 2 on the JazzWeek jazz radio chart. Reviewing it for WRTI, critic Matt Silver placed Tiemann in the lineage of organ-trio drummers running from Elvin Jones and Grady Tate to Byron Landham, praising the group's tight, danceable groove and noting that Tiemann built the record around supporting his sidemen rather than showcasing his own playing.

Tiemann's connection to guitarist Roni Ben-Hur runs through two distinct projects. He is the drummer on Love Letters (2023, Mighty Quinn Records), which Discogs bills as a genuine four-way co-credit, "Roni Ben-Hur, Ingrid Jensen, Ugonna Okegwo, Jason Tiemann," rather than a Ben-Hur leader date with sidemen. In 2026 he also played drums in the touring sextet Ben-Hur assembled to perform material from his Abriendo Puertas album live at Dizzy's Club, Jazz at Lincoln Center, on June 25, 2026, alongside trumpeter Ingrid Jensen, pianist Ray Gallon, bassist Martin Wind and vocalist Marianne Solivan. That studio album itself was recorded in Havana with an entirely different, all-Cuban band; Tiemann does not appear on it. He currently serves on the jazz faculty of the Jackie McLean Institute of Jazz at the Hartt School, University of Hartford, and continues to record and tour, appearing on projects including vocalist Alma Micic's Helen Merrill tribute Lilac Wine (2026, Venus Records) with saxophonist Eric Alexander.

Tiemann draws openly on Philly Joe Jones, Tony Williams, Elvin Jones and Billy Higgins, and his most visible work as a leader, the organ trio, put him in explicit critical company with that lineage's organ-combo specialists: reviewing T-Man, WRTI's Matt Silver placed him alongside Elvin Jones, Grady Tate and Byron Landham as drummers who thrived in that format, praising a tight, propulsive feel built for dancing rather than for solo display. His broader freelance career, largely on hard-bop and soul-jazz-leaning independent labels such as Posi-Tone, Cellar Live and SteepleChase, reflects a working drummer's ethic: he is prized as a reliable, swinging section player across a wide range of frontline instrumentalists rather than as a stylistic innovator, and his own leader dates emphasize ensemble feel and sideman support over drum spectacle.