He was born on October 19, 1970 in Genoa, Italy. He is an Italian director, designer and storyboarder.
He moved to New York at the age of 20 to study animation at the School of Visual Arts and Illustration of the Fashion Institute of Technology.
His first years working in for an animation studios as a storyboard artist for Ice Age at Blue Sky Studios and designer of some TV series for Disney Channel. He then started working for Pixar Animation Studios as a story artist. The first projects that involve him are Brad Bird's Ratatouille, Pete Docter's Up, both Oscar winners for best animated feature film.
In 2011 Casarosa made his debut as a director with the short film La Luna, in theaters with the Pixar's feature The Brave (2012). With this short movie he received his first nomination for the Academy Award.
In 2021 debut has director of the animated feature film Luca set in Italy Riviera.