In 2002, Malgarini made his film debut in The United States of Leland (released in 2004), playing a six year old boy in flashback scenes.
In 2003, he played the role of Harry Coleman in Disney's comedy hit Freaky Friday, starring Jamie Lee Curtis and Lindsay Lohan.
He appeared with Tom Hanks in a test film to develop the "performance capture" technology for The Polar Express in 2004.
Malgarini appeared as Benjy in the film adaptation of 2006 of How to Eat Fried Worms, the beloved gross out children's novel by Thomas Rockwell.
[3] According to an interview with Malgarini on his official site, he starred as the main character Ugly in the musical Honk!.