Gwilt spent most of 2006 playing with St Kilda's then VFL affiliate team, the Casey Scorpions. He returned with a total of eight games in 2007, with his best being a 21 possession game against Carlton at Docklands Stadium. He was nominated for the AFL's Army Award in Round 11 of that year. Gwilt struggled for opportunities early in 2008 but returned to the senior side in Round 11. He enjoyed better form after being played as a forward, including a good performance in St Kilda's 2008 semifinal win against Collingwood.