A native of Hollis, Queens, multi-instrumentalist, songwriter, arranger, producer, and engineer Om’Mas Keith was born to jazz instrumentalist Michael Keith and vocalist Mekea Keith. The first instrument he picked up was the drums, but he was quick to develop his musicianship along with familiarizing himself with several aspects of the music industry, from the recording process up. While still a teenager, Keith held an internship position at the RCA label, was taught by Max Roach at the University of Massachusetts, and worked beside Run-D.M.C.’s Jam Master Jay. One of his earliest high-profile collaborations came with the L.A.-based group Raw Breed, whose Blood, Sweat & Tears album featured his input.
In 2000, Keith aligned with Raw Breed associate Shafiq Husayn and Taz Arnold as Sa-Ra Creative Partners. The trio produced tracks for Bilal, Pharoahe Monch, and Jurassic 5before debuting as a recording group in 2004 with singles released on ABB and Ubiquity. As the group blossomed with full-length projects for Babygrande and Ubiquity, all three members continued to operate separately and together on a number of albums, including Jay-Z's Kingdom Come, Rick Ross' Rise to Power, Jill Scott's Real Thing, Erykah Badu's New Amerykah, Pt. 1, and Husayn’s own Shafiq En’ A-Free-Ka.
On a relatively underground level, Keith collaborated with Africa Hitech's Mark Pritchard (on "Wind It Up," a 2009 single for Hyperdub), as well as Subeena and Jamie Woon (on a 2009 single for Planet Mu). In late 2010/early 2011, just after Keith worked with Diddy on the Making His Band television series and Last Train to Paris album, he released his first solo single, “Uh Oh It's Love,” a limited-pressing single.
Around the same time, Fall Out Boy's Patrick Stump released Truant Wave, an EP featuring production and vocals from Keith. After co-producing Frank Ocean's Grammy-nominated 2012 album Channel Orange, he self-released his own album, the freaky City Pulse, and made it available as a free digital download in January 2013. Keith was credited for his work on Jay Z and Kanye West's 2011 album, Watch the Throne. In 2013, alongside producing on Channel ORANGE, he released his first independent album City Pulse and was credited on Odd Future's Earl Sweatshirt's album Doris.
In August 2016, Frank Ocean released Endless and Blonde, crediting Keith as a contributor on both. Blonde's single Nikes was produced by Keith, and he received writing credits on eleven other tracks on the album.
In November 2016, Keith was credited on Brockhampton member Kevin Abstract's sophomore album, American Boyfriend: A Suburban Love Story.