He also made a leap to the big screen, with his debut performance in "Boiler Room" (2000) opposite Ben Affleck and Giovanni Ribisi. The same year he was cast in the title role in Hillary Birmingham's family psychodrama "The Truth About Tully" and portrayed a driven student filmmaker in the sequel to "Urban Legends, Urban Legends: Final Cut." He next surfaced in the failed tough-guy noir "Poolhall Junkies" (lensed 2001) with Chazz Palminteri and Rod Steiger, and took a role in the crime drama "City by the Sea" (2002) as part of the ensemble led by Robert De Niro. De Niro famously encouraged Mount to go for the "Crossroads" role, as Spears' love interest, that would certainly raise his public profile, and even read Spears' dialogue in the script to help Mount master his lines. Although Mount briefly became a fixture in teen magazines, but he did not allow himself to be pigeonholed as a mainstream actor and was next seen in the second no-frills "Project Greenlight" feature "The Battle of Shaker Heights" (2003) as Shia LaBeouf's rival for his dream girl's affection.