Smith's best known for co-writing and serving as the primary producer for Ellie Goulding's debut album Lights, which was met with critical and commercial success.
Smith has co-written and produced several hits during his music career, including: "Good Thing" by Zedd and Kehlani, "Crybaby" by Paloma Faith, and "I'll Be There" by Jess Glynne which went to number one in the UK and was nominated for Best Single at the 2019 Brit Awards.
He met Ellie Goulding during his final year and together they started creating what would become her debut album, which was then signed to Polydor Records a few months after he graduated.
[9] In March 2014, the track "Dead In The Water" that he co-wrote and produced with Ellie Goulding was included in the promotion and soundtrack for the film Divergent,[10] which opened at No.1 at the Worldwide Box Office.
[14] In August 2024, Smith released his first song as a lead artist since 2011, titled "Leave Me Slowly" which he co-wrote with longtime collaborator, Ellie Goulding and Sarah Troy.