Richard Linklater cast his daughter Lorelei Linklater as Samantha because she always sang and danced around the house and wanted to be in his movies. At about the third or fourth year of filming, she lost interest and asked for her character to be killed. Linklater refused, saying it was too violent for his planning (Lorelei eventually regained her enthusiasm and continued with the project).
Ethan Hawke presents his fictional son with the gift of the Black Album on his fifteenth birthday. In real life, Ethan Hawke compiled the individual Beatles songs into the Black Album to help his daughter Maya deal with the breakup of his marriage with Uma Thurman.
Ellar Coltrane, who plays the boy of the title, was 7 years old when the movie started filming and 19 when it finished.
Each year of Mason's life is covered in an average of fourteen minutes of screen time.
During the 12-year shoot, both Ethan Hawke and Patricia Arquette actually experienced divorces, re-marriage, and had another child.