Kayvan is best known for his part in Fonejacker, a prank call-based show part of Comedy Lab for Channel 4 in 2007. He has also starred in the medical drama Holby City as the character Reza Abbassi, in the spy series Spooks alongside Keeley Hawes and in the Academy Award-winning film Syriana alongside Matt Damon and George Clooney.

Novak also provides voice work for various characters in video games such as Wallace & Gromit: The Curse of the Were-Rabbit and in the ITV spoof sketch show Headcases.