Originally a construction worker, Welling was discovered in 1998 at a party in Nantucket by a catalog camera scout who suggested he try modeling. Welling modelled for Louisa Modeling Agency until 2000, when he relocated to Los Angeles. There he modelled for Tommy Hilfiger, Abercrombie & Fitch, and Calvin Klein while pursuing an acting career. In 2000, Welling appeared in Angela Via's music video "Picture Perfect" where he played Vía's love interest. Welling has said that he did not like modelling and that he was not good at it because it was all on the outside or from an external point of view. He pursued acting because he wanted to express a range of emotions, but Welling still models occasionally and appeared in the May 2008 issue of Vogue, the so-called Superhero Issue. In his first major acting role, Welling played karate teacher Rob "Karate Rob" Meltzer, a younger love interest of Amy Gray (Amy Brenneman) in the second season of the CBS legal drama Judging Amy, which aired in 2001. Welling was originally signed for three episodes; after receiving enthusiastic fan reviews, the producers kept him for three more. Welling also had a small role in the UPN science fiction sitcom Special Unit 2, and he appeared in the pilot episode of the FOX sitcom Undeclared.