A high school athlete, Welling initially worked in construction and, in 1998, he successfully modeled men's clothing for several popular brands. In 2000, he made a successful transition to television. He has been nominated for and received several awards for his role as Clark Kent. In 2001, he had a recurring role as Rob "Karate Rob" Meltzer in the second season of the CBS legal drama Judging Amy. He has also been involved behind the camera as an executive producer and a director. His films include Cheaper by the Dozen (2003), Cheaper by the Dozen 2 (2005), The Fog (2005), Draft Day (2014) and The Choice (2016).