His involvement with Rooster Teeth started with writing music for the popular web series Red vs. Blue alongside the band Trocadero, to whom he was a keyboardist and met as they wanted to record in his studio.
His music was featured on the show beginning with singles during Season 8 (Revelation) and continuing in Season 9 and Season 10. His other work includes music for Rooster Teeth shows The Strangerhood and X-Ray and Vav.
Jeff is a multi-instrumentalist, playing keyboards, guitar and bass. He is also an Assistant Professor at Berklee College of Music. Other artists featured in his songs include his daughter, Casey Lee Williams, as well Lamar Hall and his ex-wife, Sandy Lee Casey. Alex Abraham, Mason Lieberman and Steve Goldshein are among the other composers who have worked with him on the RWBY soundtrack.
At RTX 2014, Jeff and Casey performed an acoustic set of songs from the RWBY soundtrack live at the RWBY Music Panel. The pair performed again at RTX 2015 alongside Video Game Orchestra and Barenaked Ladies. During the set, Jeff gave a speech about his work with Rooster Teeth and close partnership with the now deceased series creator Monty Oum. During RTX 2016, Jeff Williams performed songs from the RWBY soundtrack live at Austin City Limits.
In 2015, Jeff Williams released 8 Tracks, an app for the iPhone which allows users to turn individual tracks, such as vocals, guitar, bass and drums, on or off to create new on-the-fly mixes of songs from the RWBY soundtrack.