Milo Coy
Stan
Jack Black
Grown Up Stan (voice)
Lee Eddy
Mom
Bill Wise
Dad
Natalie L'Amoreaux
Vicky
Josh Wiggins
Steve
Jessica Brynn Cohen
Jana
Sam Chipman
Greg
Danielle Guilbot
Stephanie
Zachary Levi
Kranz
Glen Powell
Bostick
Larry Jack Dotson
Grandfather
Mona Lee Fultz
Grandmother #1
Jennifer Griffin
Grandmother #2
Holt Boggs
Sam The Rocket Man
Reese Armstrong
Tony
Natalie Joy
Music Class Teacher
Suzanne Deal Booth
Science Teacher
Chris Olson
Principal Cowan
Samuel Davis
Pinball Buyer
Mia Gonzalez
Statue-Maker Kid
Brian Villalobos
Bales
Chris Zurcher
Jack
Alexander Fink
Kid on Astroway
Zia Kinzy
Young Lady on Astroway
David DeLao
Mr. St. George
Noah Randall
Drive-In Employee
Athena Wintle
Mindy
Xavier Patterson
Emanuel
Nick Stevenson
SIMSUP
William Carroll
Abominable Snowman
Avery Joy Davis
Lisa (uncredited)
Christian Moran
Hoodlum (uncredited)
Nicholas Andrew Rice
NASA Controlman (uncredited)
Keslee Blalock
AstroWorld Kid (uncredited)
Brent A. Riggs
Service Station Attendant (uncredited)
P. Michael Hayes II
SIMSUP (uncredited)
Flint Nattinger
Laughing Boy (uncredited)