Joaquin Phoenix as Beau Wassermann

Patti LuPone as Mona Wassermann

Amy Ryan as Grace

Nathan Lane as Roger

Kylie Rogers as Toni

Denis Ménochet as Jeeves

Parker Posey as Elaine Bray

Zoe Lister-Jones as Young Mona

Armen Nahapetian as Teen Beau

Julia Antonelli as Teen Elaine

Stephen McKinley Henderson as Therapist

Richard Kind as Dr. Cohen

Hayley Squires as Penelope

Julian Richings as Strange Man

Bill Hader as UPS Guy

Alicia Rosario as Liz

James Cvetkovski as Boy Beau

Catherine Bérubé as Hero Beau's Wife

Stephanie Herrera as Martha

Bradley Fisher as Birthday Boy Stab Man

Peter Seaborne as Ceiling Man

Michael Esper as Officer Johnson

Manuel Tadros as Cheapo Depot Cashier

Karl Roy as Man with Face Tattoos

Marc-André Brisebois as Comatose Junkie

Tyrone Benskin as Rattled Businessman

Ernest-James Chuipka as Crazy Man

Archie Madekwe as Laughing Man

Greg Halpin as Crust Punk (Eye Gouger)

Luis Oliva as Crust Punk (Eyes Gouged)

Charles Hardy as Boat Boy

Marie-Michelle Garon as Fraught Mother Looking for Boat Boy

Maev Beaty as Angel / Play Narrator

Patrick Kwok-Choon as Orphan Hero

Michael Gandolfini as Beau’s Son

Théodore Pellerin as Beau’s Son

Mike Taylor as Beau’s Son

Luke Alexander James McPhail as Hero Beau's Young Son

Ryan S. Hill as Hero Beau's Young Son

Bentley Hughes as Hero Beau's Young Son

Kwasi Songui as Orphan Ladybug Man

Sylvain Landry as Orphan Man w/Mandolin

Tristan D. Lalla as Costume Designer Orphan

Emmanuel Schwartz as Orphan Chorus Member

Cat Lemieux as Orphan Chorus Member

Lily Bird as Samanda

Arthur Holden as Duncan / God on Cloud / Hero Beau’s Wife

François Paquette as Yesekov's Body

Alex Bisping as Orphan Production Designer

Lucas Gosselin as Orphan Papa Boy

Joe Cobden as News Correspondent (Brian Galloway)

Harry Standjofski as Superintendent / Catering Manager

Anana Rydvald as Teen Elaine's Mother

Isabelle Brabant as Nurse

Tarah Schwartz as News Anchor (BB Stab Man)

Barry Morgan as News Anchor (MW Obit)

David Mamet as Rabbi

John Walsh as Hearse Driver

Karim Babin as Caterer

Lee Villeneuve as Mona Henchman Who Throws Lawyer

Steve Newburn as Monster Puppeteer

Kayla Dobilas as Monster Puppeteer

Gord Robertson as Monster Puppeteer

Pamela Iveta as Monster Puppeteer

Jason Detheridge as Monster Puppeteer

Luz Tercero as Mourning Woman

Geneviève Marin as Elaine Body Double

Julien Fortin as Beau's Twin in Attic

Marc-André Casavant as Dancer (uncredited)

Ari Aster as A Neighbor of Beau's (uncredited)