Charles Chu
— Joon
Ryan O'Nan
— Butch Blossom
Caitlin Stasey
— Cherry Swade
Alan Cumming
— Uncle
Richard Kind
— Fred
Melanie Lynskey
— Miss Shoemaker
Christopher Rodriguez Marquette
— Buddy
Annie Potts
— Aunt
Mercedes Ruehl
— Mrs. Fefterg
Dan Bakkedahl
— Principal Cochette
Grant Shaud
— Tim
Philip Ettinger
— Donnie
Mary Rachel Quinn
— Deborah
Lance Tafelski
— Wolf
Steve Heinz
— Security Guard
Peter Jae
— Joon's older brother