Smith did not achieve mainstream success in his solo career but continued writing songs both alone and with his close friend and roommate Ralph Pelleymounter of the band To Kill a King.

[5] After finishing his studies, Smith returned to London, where he continued pursuing his solo career, and eventually formed Bastille with Chris "Woody" Wood, Kyle Simmons, and Will Farquarson.

In 2015, Smith featured as vocalist for the song "La Lune", produced and written by the French electronic musician Madeon for his 2015 album Adventure.

In November 2019, a cover of the REO Speedwagon song "Can't Fight This Feeling" sung by Smith was used in the John Lewis & Partners 2019 Christmas advert.

[7] In May 2024, he was invited by Greenpeace on a trip to the Sargasso Sea on their ship the Arctic Sunrise to learn about and raise awareness for their campaign to protect the area.

[10] Smith writes and arranges some of Bastille's songs, apart from remixes and covers, and worked with friend Mark Crew to produce Bad Blood and Wild World.