Thom began his professional career at the age of 16 with his first role in the Network Ten telemovie Emerald Falls alongside actors Vince Colosimo, Georgie Parker and Catherine McClements. Through his early teen years he also starred in four Australian short films Vafadar, Smith, The Ground Beneath, Voyeurnet with Academy Award nominee Stuart Parkyn. For his role in The Ground Beneath, he received a nomination for Best Young Actor at the 2008 AFI Awards and won the Best Actor awards at the St Kilda Film Festival, Ourense Film Festival & Mas Sorrer Film Festival in

Spain.

In 2009 Thom joined the cast of Home & Away as Dexter Walker, and starred in the feature film Beneath Hill 60. He then joined the cast of the acclaimed television series, Dance Academy, as Samuel Lieberman. In 2012, Thom starred in the Robert Carter drama Thirst alongside Hanna Mangan-Lawrence, Myles Pollard and Victoria Haralabidou. After relocating to the US, Thom broke through with a lead role in his first American production, Halo 4: Forward Unto Dawn for which he was nominated for Best Actor at the 2017 Streamy Awards in Los Angeles. Thom’s next US credit was as series regular Kip Wampler in the NBC television series Camp alongside Rachel Griffiths before returning to Australia in 2016 for the lead role in the feature film Downriver opposite Kerry Fox where he received the Best Actor award at the Iris Prize Film Festival in Cardiff, Wales.

After a brief hiatus from acting, Thom returned to the screen in 2020 to work on Stan Australia's highly anticipated series Eden as Bodie Palmer and guest starred in Season 3 of the acclaimed TV series Mr Inbetween. Since his return he has had roles in Stan’s Exposure, ABC’s Ladies in Black, Netflix’s Apple Cider Vinegar & The Survivors and a leading role in Goran Stolevski’s queer romance film Of An Age for which he received Best Actor nods at the 2024 AACTA Awards and Film Critics Circle of Australia Awards.