Tyldum was educated at the School of Visual Arts in New York. He originally wanted to be a musician but abandoned the ambition when he entered film school. Tyldum currently lives in Beverly Hills with his wife Janne and their child. They still maintain a house in Norway.
He had his feature film debut with Buddy in 2003, a film that won great popular and critical acclaim. Previously he had worked in television, music videos, commercials and short films. He had been named Film Talent of the Year by the newspaper Dagbladet in 1999.
Since Buddy, he has made the movie Varg Veum - Flan engler (Fallen Angels) in 2008 and Headhunters (Hodejegerne) in 2011. Headhunters is based on the 2008 novel by same name written by Jo Nesbø. It became the highest-grossing Norwegian film of all time.