Smelt's career as a civil engineer led to him having several different roles over the years, including designing bridges for GHD, project engineer for the Department of Environment, Land, Water and Planning (where he constructed different bridges and culverts in Victoria), and a design risk manager in the Regional Rail Link project, where he supported extra rail lines and services to regional Victoria. He then also completed work as the Transport Sector Lead and Principal Engineer at Infrastructure Victoria, which produced the first 30-year infrastructure strategy in the state.[citation needed]
Smelt and his wife, Susannah, moved to Darwin in 2019 to be closer to his wife's family.[5]
In 2021, he became a candidate at the local government elections and was elected to the City of Darwin Council on a platform of making Darwin the ‘Outdoor Capital of Australia’.[6]
In 2026, Smelt was announced as the Labor Party candidate for the 2026 Nightcliff by-election,[7] where he won against the Greens candidate Suki Dorras-Walker.[8][9]