Kal Penn kicked off his acting career in 1998 with a role in ‘Express: Aisle to Glory,’ a comedy short film directed by Jonathan Buss. The following year, he made his television debut in the TV film ‘Brookfield.’ Around the same time, he appeared in the episode "Beer Bad" of the supernatural drama television series ‘Buffy the Vampire Slayer.’ He also made a brief appearance in ‘Angel,’ the spin-off series of ‘Buffy the Vampire Slayer.’
In 2001, Kal Penn starred as ‘Ajay Pandya’ in the American comedy film ‘American Desi’ directed by Piyush Dinker Pandya. He went on to appear in movies like ‘Van Wilder’ (2002), ‘Love Don't Cost a Thing’ (2003), ‘Malibu's Most Wanted’ (2003). The year 2004 saw the release of the stoner comedy film ‘Harold & Kumar Go to White Castle’ and gained considerable recognition for his portrayal of 'Kumar Patel' in the film.
In 2007, Kal earned a lot of appreciation for his performance in ‘House,’ the television medical drama where he starred as ‘Lawrence Kutner’. Penn remained on the show for 2 seasons before leaving it in 2009. As for the big screen, Kal Penn went on to appear in movies like ‘The Namesake’ (2006), ‘Superman Returns’ (2006), ‘Harold & Kumar Escape from Guantanamo Bay’ (2008) where he reprised his role as Lawrence Kumar, ‘Dementamania’ (2013), ‘Speech & Debate’ (2017).
Kal Penn played the role of ‘Mark’ in the 2021 horror-comedy film ‘Untitled Horror Movie.’ He is currently seen hosting the television show ‘Money Hungry.’ Penn will be next seen in the upcoming film ‘Something's Wrong with Rose.’ The movie is both written and directed by ‘Parker Finn.’