Lucy Punch was first seen on-screen in the Episode: "Orphans" of the American-French television series ‘The New Adventures of Robin Hood’ in 1998. She went on to make small appearances in ‘Renford Rejects’ (1999), ‘Days Like These’ (1999), and ‘Big Bad World’ (1999-2001), before making her film debut with the 2000 British comedy film ‘Greenfingers’ directed by Joel Hershman.
She was next seen in television series and films such as ‘Cinderella’ (2000), ‘Midsomer Murders’ (2001), and ‘Dinotopia’ (2003). In 2004, Punch joined the main cast of the British television medical comedy-drama series ‘Doc Martin’ where she played the role of ‘Elaine Denham.’ She got herself another leading role in 2007 in the sitcom series ‘The Class.’
In 2011, Punch starred as 'Amy Squirrel' in the American comedy film 'Bad Teacher.' While the film received a lukewarm response from critics, it managed to become a phenomenal box office success, managing to gross over $216.2 million on a $20 million budget. The following year, she starred as 'BJ' in the single-camera sitcom television series 'Ben and Kate.' Punch remained a part of the series till it went off-air in 2013.
Punch became a part of the sitcom series 'Motherland' in 2016. She still appears on the show and plays the character of 'Amanda.' In 2021, she joined the cast of the American adult animated sitcom ‘The Prince.’ She voices ‘Catherine, Duchess of Cambridge’ on the show. That same year, she also starred in the comedy horror film ‘Silent Night’ directed by Camille Griffin. The film premiered at the 2021 Toronto International Film Festival and opened to positive reviews from critics.