Britell was raised in a Jewish family, in New York City. He graduated from the college preparatory school, Hopkins School, in 1999. Britell is a graduate of the Juilliard School's Pre-College Division and a Phi Beta Kappa graduate of Harvard University in 2003. At school, he was a member of the instrumental hip-hop group, The Witness Protection Program, where he played keyboards and synthesizers. Britell is part of an emerging generation of composers and artists who draw from an eclectic range of influences. His work is inspired by Rachmaninoff, Gershwin, Philip Glass, and Zbigniew Preisner as well as by producers Quincy Jones and Dr. Dre.
In 2008, Britell gained wide notice performing his own work "Forgotten Waltz No. 2" in Natalie Portman's directorial debut Eve. He collaborated again with Portman, writing music for the film New York, I Love You. In 2011, Britell performed on piano with violin virtuoso Tim Fain in "Portals." The multimedia project also featured performances by Craig Black, Julia Eichten and Haylee Nichele and featured music by Philip Glass and Nico Muhly, poetry by Leonard Cohen and choreography by Benjamin Millepied. Vogue Magazine called Britell among "...the most talented young artists at work..."
As a film Composer, Britell created the music for the movie Gimme the Loot directed by Adam Leon. The film would go on to compete in the Un Certain Regard section at the 2012 Cannes Film Festival. It won the Grand Jury Prize at the SXSW Film Festival in 2012. The music for the film garnered special praise from New York Magazine and Variety. Britell's film composing career continued in 2012 with the scoring of Michele Mitchell's PBS documentary Haiti: Where Did the Money Go? The film, which aired over 1,000 times in the United States on PBS stations and was screened at the Oakland Film Festival and the Bolder Life Film Festival in 2012, is the winner of the 2013 National Edward R. Murrow Award for Best News Documentary and winner of a 2012 CINE Golden Eagle Award and a CINE Special Jury Award for Best Investigative Documentary.
As a film Producer, Britell produced the short film Whiplash, directed by Damien Chazelle, which won the Jury Award for Best US Fiction Short at the 2013 Sundance Film Festival. He subsequently helped produce the feature-film Whiplash, also directed by Chazelle and starring Miles Teller and J.K. Simmons. The Whiplash feature won Sundance's 2014 Jury Prize and Audience Award, and went on to get 5 Oscar nominations (including Best Picture) and won 3 Oscar awards. Britell also wrote and produced the track "Reaction," produced the track "When I Wake," and performed and produced "No Two Words" for the film's Soundtrack.
Britell has produced numerous other projects with The Amoveo Company, a multimedia production company and artists' collective that he co-founded with Benjamin Millepied. Amoveo is a multimedia production company and artists' collective active in digital media, television, and film. Notable Amoveo projects include "Naran Ja," a short film directed by Oscar-winning Director Alejandro G. Iñárritu, "Passage To Dawn," a short film created for Maiyet's Spring/Summer 2015 collection, and "Hearts and Arrows", a short film of Benjamin Millepied’s ballet of the same name which debuted at the L.A. Film Festival in June 2015. Working with Amoveo, Britell created the "Baileys Nutcracker (Britell Remix)", which was used by Baileys for its successful "Baileys Nutcracker" campaign. The full-length version of the Baileys Nutcracker spot has over 2.8 million views on YouTube as of June 2015.
Britell scored Director Adam Leon's film Tramps in 2016, with Netflix acquiring worldwide distribution rights to the film at the 2016 Toronto International Film Festival.
Britell scored Fox Searchlight's tennis biopic Battle of the Sexes, directed by Jonathan Dayton and Valerie Faris, and released in 2017.
