Harold LaShaun "Shaun" Martin was born in Dallas on August 23, 1978, and grew up in the Oak Cliff neighborhood. His mother started him on piano lessons at four, and his teacher Carolyn Campbell taught him to read and write music and introduced him to jazz. Church supplied the rest of the education: by five he was playing piano and organ in services, and the gospel repertoire sat alongside the classical and jazz material he studied at home. He attended Dallas's Booker T. Washington High School for the Performing and Visual Arts, then Weatherford College and the University of North Texas, where he earned a Bachelor of Applied Arts and Sciences degree in 2001. Norah Jones was a classmate at both Booker T. Washington and North Texas.

His professional career began before he graduated. While still a teenager he started working with the gospel choir director Kirk Franklin as a keyboardist and organist in God's Property, the Dallas choir that recorded with Franklin in the 1990s and had a hit with "Stomp." The live album God's Property from Kirk Franklin's Nu Nation (May 27, 1997) lists him on keyboards and organ. He kept touring with Franklin through his college years, and a faculty member at North Texas worked out a class schedule around the road dates. In the 2000s he moved into production with Franklin, co-producing Hero (October 4, 2005), which won the Grammy for Best Contemporary Soul Gospel Album at the 2007 ceremony. He is credited with four Grammy Awards for his work with Franklin in the gospel album categories, among them Hello Fear (Best Gospel Album, 2012) and Long Live Love (Best Gospel Album, 62nd Grammy Awards, January 2020). He also served as Franklin's music director, and in 2023 Franklin described him as his right hand and a musical partner of more than 25 years.

The same student years brought him into the R&B world. He joined the band of Erykah Badu not long after her debut Baduizm and contributed to her second album, Mama's Gun (Motown, November 2000), where Discogs credits him with keyboards on four tracks and a co-production credit on one. He later played in Chaka Khan's backing band and worked with Fred Hammond, Kim Burrell, N'Dambi and Myron Butler, among others. Alongside the touring he served as minister of worship and music and Sunday-service bandleader at Friendship-West Baptist Church in Oak Cliff, one of the largest churches in the country, a post he left to concentrate on his own records.

Snarky Puppy had formed among North Texas students, and when its members began holding jam sessions in Dallas they invited Martin to sit in. He has said his first gig with them was punishing because he had been away from aggressive jazz playing for a while. He became a regular member, and he is credited on groundUP (2012), We Like It Here (2014), Family Dinner - Volume 2 (2016), Culcha Vulcha (2016), Immigrance (2019), Live at the Royal Albert Hall (recorded November 14, 2019) and Empire Central (recorded in Dallas in March 2022, the band's last album with him). Three of those albums, Culcha Vulcha, Live at the Royal Albert Hall and Empire Central, won the Grammy for Best Contemporary Instrumental Album (2017, 2021 and 2023), which with the four Franklin wins gives him seven Grammys in all. On the records he played Fender Rhodes, Moog, Mellotron, clavinet, talkbox and vocoder, and his solos on "Thing of Gold," "Quartermaster" and "Flood" raised his profile with the band's audience. Bandleader Michael League said in a 2022 interview that Martin, drummer Robert "Sput" Searight, keyboardist Bobby Sparks and a few other Dallas players made the group funkier, tighter and more emotional than the college band it had been. With the band, Martin also backed David Crosby on the 2017 album Sky Trails, playing synthesizers.

His own records came later and drew on all of this. 7 Summers (July 7, 2015, Shunwun Music and Ropeadope) is a twelve-track album that blends R&B and gospel with funk and jazz influences, written, arranged and produced by Martin, with a string section arranged by Maurice Herd and guests including guitarist Mark Lettieri. Focus (July 20, 2018, Ropeadope) is a piano trio record made in two days at Kirk Franklin's studio, with bassist AJ Brown and drummer Jamil Byrom (Keith Taylor and Robert "Sput" Searight play on the title track), and it includes Joe Henderson's "Recorda-Me" and the standard "Body and Soul." Three-O (November 13, 2020, Ropeadope) is a trio date with bassist Matthew Ramsey and drummer Michael "Blaque Dynamite" Mitchell that leans toward synthesizers and programming, and it covers John Coltrane's "Naima" and Mongo Santamaría's "Afro Blue."

Martin suffered a massive stroke on April 17, 2023, and was under constant medical care for more than a year afterward. He passed away on August 3, 2024, at the age of 45, from complications following the stroke. He was survived by his wife, Monica Wilson Martin, and their son, Harlem. Snarky Puppy called him a music legend and a luminous human being in its statement. A benefit concert to honor him and help with his medical costs, titled A Salute to Pianist Extraordinaire Shaun Martin, was scheduled for September 14, 2024 at the Black Academy of Arts and Letters in Dallas, with an announced lineup that included Erykah Badu, Snarky Puppy, Norah Jones, Robert Glasper, Terrace Martin and Cory Henry.

Most of Martin's public work was gospel and R&B: the Grammys he won with Kirk Franklin are gospel awards, his sideman and production credits run through Erykah Badu, Chaka Khan and Fred Hammond, and the church organ and piano he learned as a child were the base of everything he played. The jazz side is real and documented rather than incidental. He was introduced to jazz as a small child, studied at the University of North Texas, known for its jazz program, spent more than a decade as a keyboardist in Snarky Puppy, one of the best-known jazz-fusion bands of the 2010s, and made Focus, an acoustic piano trio album built around a Joe Henderson tune and a standard. In the liner note for Focus he named Beethoven, Bill Evans, Handel and Herbie Hancock among the pianists and composers he studied, and a Bandcamp Daily reviewer heard the swing and blues phrasing of Gene Harris, the poetic touch of Evans and the dynamic range of Ahmad Jamal in the playing, along with echoes of the Ray Brown trio. His Snarky Puppy years added a different toolkit, with Moog bass lines, talkbox and vocoder, and a groove sense drawn from Dallas funk, hip-hop and go-go; he also founded a go-go band of his own.