Kyle Gallner was born in Philadelphia, Pennsylvania in 1987. Gallner may be best known to television audiences for his role as Cassidy "Beaver" Casablancas on Veronica Mars. Gallner joined the cast toward the end of the show's first season, in May 2005, and became a main cast member.

Gallner also appeared on television on Smallville, Law & Order: Special Victims Unit, Judging Amy, Big Love, and Jack & Bobby. He has appearances in films such as Wet Hot American Summer, Red Eye, and Finding Home.