Monaghan first came to national attention in 2003 for his role as Winthrop Paroo opposite Kristin Chenoweth and Matthew Broderick in the ABC television adaptation of "The Music Man". When recounting the decision to cast the 9-year-old Monaghan, director and executive-producer Jeff Bleckner explained, "There are some people, when you put them up on film, they sort of pop off the screen at you. That's how it was with Cameron. From the second we saw him, he was it. We were looking for anybody who had that wonderful appeal. And Cameron had it."