Kieran Culkin
Igby
Claire Danes
Sookie
Jeff Goldblum
D.H.
Jared Harris
Russel
Amanda Peet
Rachel
Ryan Phillippe
Oliver
Bill Pullman
Jason
Susan Sarandon
Mimi
Rory Culkin
10-Year-Old Igby
Peter Anthony Tambakis
13-Year-Old Oliver
Bill Irwin
Lt. Smith
Kathleen Gati
Ida
Gannon Forrester
Little Cadet
Celia Weston
Bunny
Elizabeth Jagger
Lisa Fiedler
Nicholas Wyman
Suit
Cassidy Ladden
Hockey Player
Erin Fritch
Hockey Player
Jim Gaffigan
Hilton Manager
Arnie Burton
Front Desk Clerk
Eric Bogosian
Mr. Nice Guy
Cynthia Nixon
Mrs. Piggee
Mistress Formika
Peeka
Glenn Fitzgerald
Surfer Tommy
Reg Rogers
Therapist
Danny Tamberelli
Turtle
David Arrow
Waiter
Ronobir Lahiri
Intern
Gore Vidal
First School Headmaster (uncredited)