In 2006, he had a main role in the film These Foolish Things, which also starred Terence Stamp, Lauren Bacall, and Anjelica Huston. The film's lead Actress was Zoe Tapper, who guest-starred in an episode of Cutting It.
In 2007 David played Billy the Kid in the BBC's mini series The Wild West. In 2010 he played Jesus in Mark Haddon's play Polar Bears at the Donmar Warehouse.
From 2011 to 2014, he played DS Joe Ashworth in the ITV detective series Vera alongside Brenda Blethyn.
Orthodox, Leon's third short film as writer/director, was accepted into several international festivals including the 58th BFI London Film Festival. The feature-length version of Orthodox was completed in 2015.
