Meryl Streep
Florence Foster Jenkins

Hugh Grant
St. Clair Bayfield

Simon Helberg
Cosmé McMoon

Rebecca Ferguson
Kathleen Weatherley

Nina Arianda
Agnes Stark

Stanley Townsend
Phineas Stark

Allan Corduner
John Totten

Christian McKay
Earl Wilson

David Haig
Carlo Edwards

John Sessions
Dr. Hermann

Brid Brennan
Kitty

John Kavanagh
Arturo Toscanini

Pat Starr
Mrs. Vanderbilt

Maggie Steed
Mrs. James O'Flaherty

Thelma Barlow
Mrs. Oscar Garmunder

Liza Ross
Mrs. EE Patterson

Paola Dionisotti
Baroness Le Feyre

Rhoda Lewis
Mrs. Patsy Snow

Aida Garifullina
Lily Pons

David Mills
Augustus Corbin

David Menkin
Carlton Smith

Sid Phoenix
Corporal Jones

Tunji Kasim
Private Smith

Carl Davis
Orlando Adams

Lloyd Hutchinson
Microphone Engineer

Josh O'Connor
Donaghy

Caolan Byrne
Stagehand 2

John Guerrasio
Newspaper Vendor

Ewan Stewart
Colonel

Greg Lockett
Chuck

Cameron Cuffe
Gino

James Sobol Kelly
Edgar (Diner)

Dar Dash
Antonio

Grant Gillespie
Brooklyn Man

Philip Rosch
Archie the Doorman

Elliot Levey
Edgar Booth Cunningham, Jr.

Danny Mahoney
Clifford B. Thornton III

Mark Arnold
Cole Porter

Rosy Benjamin
Corbin's Gang

James Wallace
Corbin's Gang

Charles Streeter
Corbin's Gang

Philip Gascoyne
New York Journalist (uncredited)