Liev Schreiber

as Chuck Wepner

Naomi Watts

as Linda Wepner

Elisabeth Moss

as Phyllis Wepner

Ron Perlman

as Al Braverman

Jim Gaffigan

as John Stoehr

Michael Rapaport

as John Wepner

Pooch Hall

as Muhammad Ali

Morgan Spector

as Sylvester Stallone

Jason Jones

as Arty

William Hill

as Paddy

Wass Stevens

as Johnny Dicesare

Kelvin Hale

as Charlie Polite

Megan Sikora

as Flo Wepner

Emil Tonev

as Fight Ref

Georgia X. Lifsher

as Rachel

Catherine Corcoran

as Sandy

Sadie Sink

as Kimberly

Melo Ludwig

as Young Kimberly (aged 6)

Georgi Georgiev

as Mouthy

Mihail Nedyalkov

as Nerk

Liv Rooth

as Platinum Blonde

Joe Starr

as Manny

Leslie Lyles

as Charlotte

Velizar Binev

as Referee

Robert C. Kirk

as Warden

J.J. Kandel

as Jimmy the Cop

Jen Ponton

as Stallone's PA

Rick Zahn

as Police Captain

Ivan Martin

as Bobby Vann

Jonathan Wilde

as Dave

Zina Wilde

as Teacher

Charlie Meany

as Sports Interviewer

Mark Borkowski

as Joe

Lucinda Rogers

as Lil

Anthony J. Gallo

as Maitre'D

Shade Rupe

as 16mm Cameraman (uncredited)

Leonard Zimmerman

as Hotel Valet (uncredited)

Genko Ivanov

as Terry Hinke