By the age of nine, he was busy with voice-over work, including the voice of young Prince Derek in "The Swan Princess" (1994), and David in "All Dogs Go to Heaven 2" (1996). He then lent his voice to many animated series, including "Dennis the Menace" as the title character (1993–94), "Hey Arnold!" as Curly (1996–2002), "Crayola Kids Adventures", "Napoleon" as the title character (1997), "The King and I" (1999) as Louis Leonowens, and Walt Disney Television Animation's pilot "Kitty's Dish" (as Josh). Wylie's voice credits also include "Batman Beyond", "Pepper Ann" as Crash, "As Told By Ginger" as Ian Richton, "Midnight Club II", Jimmy Olsen in the 2007 direct-to-DVD movie, ', the roles of Fred Nerk, Nigel Thrall and Bananas B on ', "", "Ben 10", and the character Justin in "The Easter StoryKeepers".