Matthew Broderick
Richard Feynman
Patricia Arquette
Arline Greenbaum
Peter Riegert
Mel Feynman
Jeffrey Force
Young Richard
David Drew Gallagher
Harold
Raffi Di Blasio
Robert
Josh Keaton
David
James Hong
Abacus Adder
Melissa DeLizia
Young Joan
Peter Michael Goetz
Dr. Gell-Mann
Kelly Wolf
Nurse Kate
Mary Pat Gleason
County Nurse #2
Joyce Van Patten
Aunt Ruth
James Le Gros
John Wheeler
Zeljko Ivanek
Bill Price
Joshua Malina
Calculator Kid #3
Matt Mulhern
Gate Guard