Both met them during their freshman year at Western Washington University. The two did not share the same educational interests. Knight studied physics and math while Mills studied graphic design. They did not begin collaborating musically until their senior year in 2012. As a child, Knight was classically trained in piano and later learned guitar.
The band's name is taken from the name of Mills' uncle's sunken vessel. Only his uncle and one other crew mate survived. Since the spelling "Odessa" was already being used by a Scottish synth band, they instead chose to use a form of the Hungarian spelling, replacing the "ss" with "sz". The correct spelling in Hungarian is: Odessza.
Individually Mills is known as Catacombkid, and Knight is known as Beaches Beaches. In reference to how Mills got his nickname, he says, "I got into Aesop Rock and he has a song called 'Catacomb Kids.' I thought it sounded cool." On the other hand, the story behind Knight's nickname, he says, "Honestly I was high in my bedroom making music one day…"
Their debut album, Summer's Gone, was released in 2012 to much acclaim in the underground electronic music community. Odesza followed Summer's Gone with their first EP, My Friends Never Die, in 2013 and their second studio album, In Return, in 2014. The duo released the deluxe edition of In Return on September 18, 2015 via Counter Records, an extended version of the original album plus three live recordings all featuring a horn section, instrumentals, and a new track "Light" (featuring Little Dragon). On December 7, 2015, Odesza's "Say My Name" (RAC mix) was nominated for Best Remixed Recording, Non-Classical at the 58th Annual Grammy Awards. The duo's third studio album, A Moment Apart was released on September 8, 2017. On November 28, 2017, A Moment Apart was nominated for Best Dance/Electronic Album at the 60th Annual Grammy Awards; their single "Line of Sight" featuring Wynne & Mansionair was nominated for Best Dance Recording.