His father is from the Netherlands. His mother, who died when he was 12, was from Norway. Zwart himself was born in the Netherlands but grew up in Norway and is a Norwegian citizen.

Always sneaks the flag of his local soccer-club, Fredrikstad Fotballklubb (FFK), into all his movies.

His favorite movies are "Back to the Future" (1985), "Amadeus" and "A Few Good Men".

Harald Zwart donates props from his all movies such as Hamilton (1998); One Night at McCool's (2001) and Agent Cody Banks (2003) for the local cinema in his home-town of Fredrikstad. There's a "Planet Hollywood"-type museum there and in Fredrikstad, the place is popularly known as "Haraldwood". HE also has a movie theatre named after him.

The first Norwegian to become a member of the Directors Guild of America (DGA).

Directed various commercials and music videos.

Has a cameo as a sailor in the music video for a-ha's "Forever Not Yours", which he also directed. He is the sailor who hands Magne Furuholmen his guitar. He appears in a few other productions, but has since stopped.

His music video for the Norwegian singer/songwriter Jan Eggum was the first Norwegian-language video to be shown on MTV and it was made for a record low budget with his producer partner and wife Veslemoey Ruud Zwart.

In 2001, film critic Philip Wuntch of the Dallas Morning News, reviewing One Night at McCool's (2001), praised him and called it "an impressive feature debut" when in fact 1998's Scandinavian action/thriller Hamilton (1998) was Harald Zwart's feature debut.

Son Zander and daughter Stella Sophia Zwart with producer Veslemoey Ruud Zwart.

Directed the controversial video for a-ha's "Velvet", from the movie soundtrack which became a much debated video due to it's romantic portrayal of dead people. Based on images from old police crime scene photos, the video depicted the band as alive though everyone else saw them as corpses.

It was his background as a director for commercials he got his first job in Hollywood, and he has continued to direct commercials in-between his feature films. In October 2004 he directed a series of commercials for Sky TV, starring John Travolta (meant for the Italian market).

He is a very good friend of Tom Gulbrandsen.