Co-Writer and Director Mike Mills saw over one hundred actors for the role of Justin.
Scarlett Johansson was originally cast as Rebecca Crane, but she dropped out shortly before filming, and was replaced by Kelli Garner.
The soundtrack to the film was originally to consist of a number of cover songs performed by Elliott Smith, but he died before the project's completion.
Lou Taylor Pucci (Justin) and Kelli Garner (Rebecca) have also worked together on another project. In Green Day's music video for "Jesus of Suburbia", Pucci played the role of St. Jimmy/"Jesus of Suburbia" and Garner played the role of "Whatsername".