Joaquin Phoenix

as Arthur Fleck

Lady Gaga

as Lee Quinzel

Brendan Gleeson

as Jackie Sullivan

Catherine Keener

as Maryanne Stewart

Zazie Beetz

as Sophie Dumond

Steve Coogan

as Paddy Meyers

Harry Lawtey

as Harvey Dent

Leigh Gill

as Gary Puddles

Ken Leung

as Dr. Victor Liu

Jacob Lofland

as Ricky Meline

Bill Smitrovich

as Judge Herman Rothwax

Sharon Washington

as Debra Kane

Alfred Rubin Thompson

as Ernie Bullock

Connor Storrie

as Young Inmate

Gregg Daniel

as Music Teacher

Mac Brandt

as Arkham Guard

George Carroll

as Arkham Guard