Grey has been played on NTS shows including Chicago Takeover, with The Middle first played on 7 September 2018.

Brothers Kyle and Michael Trewartha grew up in Fountain Valley, California. Kyle played guitar in a metal band before releasing original songs and remixes in electronic genres such as dubstep and electro house under the name Singularity from 2011 to 2014. He also had two releases under the name Kyle Tree in 2015 and 2016. In 2013, Michael started to learn how to produce music.

They officially formed as Grey in 2015, first releasing a remix of "Where Are Ü Now" by Jack Ü, later remixing songs by artists including Zedd, Selena Gomez, Troye Sivan, Mike Posner and Ariana Grande. In 2016, they released their debut single "Starving" with Hailee Steinfeld and Zedd. Their debut EP, Chameleon, was released on September 29, 2017. In 2018, they released "The Middle" with Maren Morris and Zedd and signed to Island Records. They released the single "Want You Back" featuring Léon on January 10, 2019. On October 23, 2020 they released their 2nd EP titled "Light" and later on December 11, 2020 they released their 3rd EP titled "DARK"