Richardson landed his first acting role in 1995 at the age of nine on the ABC series Fudge, based on the stories of Judy Blume.
He played a minor role in the Disney film Toothless, alongside Kirstie Alley, Ross Malinger, and directed by Melanie Mayron.
Richardson starred as Reggie Van Dough in the 1998 Warner Home Video family comedy Richie Rich's Christmas Wish.
In 2001, Richardson fulfilled one of his dreams of working with Kevin Smith, making a small cameo in Jay and Silent Bob Strike Back.
The 2003 movie Hangman's Curse, based on a Christian novel by Frank Peretti, Richardson plays the gothic character of Ian Snyder.