James McAvoy

Dennis / Patricia / Hedwig / The Beast / Kevin Wendell Crumb / Barry / Orwell / Jade

Anya Taylor-Joy

Casey Cooke

Betty Buckley

Dr. Karen Fletcher

Haley Lu Richardson

Claire Benoit

Jessica Sula

Marcia

Izzie Coffey

Five-Year-Old Casey

Brad William Henke

Uncle John

Sebastian Arcelus

Casey's Father

Neal Huff

Mr. Benoit

Ukee Washington

News Anchor

M. Night Shyamalan

Jai, Hooters Lover

Rosemary Howard

Kevin's Mother

Lyne Renee

Academic Moderator

Peter Patrikios

Taxi Driver

Kash Goins

Flower Kiosk Worker

Roy James Wilson

Security Guy with Dog

Christopher Lee Philips

Older Worker

Ameerah Briggs

Police Officer #1

Nakia Dillard

Police Officer #2

Robin Rieger

Television Reporter

Emlyn McFarland

Diner Waitress

Dann Fink

Game Show Contestant (voice)

Bruce Winant

Game Show Host (voice)

Bruce Willis

David Dunn (uncredited)

Kim Director

Hannah (uncredited)

Robert Bizik

Bar Patron (uncredited)

Vincent Riviezzo

Detective (uncredited)

Gary Ayash

Restaurant Patron (uncredited)