Tom Welling started out as a model for the Louisa Modelling Agency. He modeled for them till 2000, before making his television debut in 2001 in the American legal drama television series ‘Judging Amy.’ He played the role of ‘Rob Meltzer’ and appeared in 6 episodes of the series. That same year, he got his breakthrough role in the American superhero television series ‘Smallville.’ He played different roles in the series, including ‘Kal-El / Clark Kent / Superman’ and ‘Bizarro.’ ‘Smallville’ ran for 217 episodes, from October 16, 2001, to May 13, 2011. In 2003, Welling made his big-screen debut in the family comedy film ‘Cheaper by the Dozen’ directed by Shawn Levy. While the film received mixed response from critics, it was a major box office success, grossing over $190.2 million against a budget of $40 million.
Welling starred as Nicholas "Nick" Castle in the 2005 American supernatural horror film ‘The Fog.’ Even though the film received a lukewarm response from critics, it managed to come out as a financial success. That same year, he also starred in ‘Cheaper by the Dozen 2,’ the sequel to the 2003 film ‘Cheaper by the Dozen.’ The film was panned by critics but was a box office success. He was next seen in films like ‘Parkland’ (2013) and ‘Draft Day’ (2014). In 2016, he starred in the romantic drama film ‘The Choice’ directed by Ross Katz. The film opened to unfavorable reviews and was a moderate success at the box office.
In 2017, Welling joined the cast of the American urban fantasy television series ‘Lucifer’ as ‘Lt. Marcus Pierce / Cain.’ He remained a part of the show until 2018. He was last seen playing the role of ‘Vincent Corbo’ in the action-adventure television series ‘Professionals’ in 2020.