Joaquin Phoenix

Arthur Fleck / Joker

Lady Gaga

Harleen Quinzel / Harley Quinn

Brendan Gleeson

Catherine Keener

Zazie Beetz

Sophie Dumond

Steve Coogan

Harry Lawtey

Leigh Gill

Gary

Ken Leung

Jacob Lofland

Sharon Washington

Social Worker

Troy Fromin

E Ward Inmate (Troy Larkins)

Bill Smitrovich

Judge Herman Rothwax