Grey consists of brothers Kyle and Michael Trewartha.
Kyle played guitar in a rock band before releasing original songs and remixes under the name Singularity. 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. 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.