Leonardo DiCaprio
John Edgar Hoover

Armie Hammer
Clyde Tolson

Naomi Watts
Helen Gandy

Josh Lucas
Charles Lindbergh

Josh Hamilton
Robert Irwin

Judi Dench
Anna Marie Hoover

Geoff Pierson
Mitchell Palmer

Gunner Wright
Dwight Eisenhower

Dermot Mulroney
Colonel Schwarzkopf

Kaitlyn Dever
Palmer's Daughter

Adam Driver
Walter Lyle

Ed Westwick
Agent Smith

Jessica Hecht
Emma Goldman

Denis O'Hare
Albert Osborne

Lea Thompson
Lela Rogers

Damon Herriman
Bruno Hauptmann

Sadie Calvano
Edgar's Niece

Amanda Schull
Anita Colby

Roberta Bassin
Roosevelt's Secretary

Emily Alyn Lind
Shirley Temple

Barbara Keegan
Bombing Witness

Gerald Downey
FBI Agent

Jeffrey Donovan
Robert Kennedy

Geoff Stults
Raymond Caffrey

Lea Coco
Agent Sisk

Aaron Lazar
Prosecutor Wilentz

David A. Cooper
Franklin Roosevelt

Kelly Lester
Head Secretary

Jack Donner
Edgar's Father

Jack Axelrod
Caminetti

Josh Stamberg
Agent Stokes

Christian Clemenson
Inspector Schell

Billy Smith
Secret Service Officer

Ken Howard
Harlan Fiske Stone

Zach Grenier
John Condon

Johnny Cicco
Young Agent

Steve Monroe
Restaurant Host

Stephen Root
Arthur Koehler

Gary Werntz
Attorney General

David Clennon
Senator Friendly

Michael O'Neill
Senator McKellar

Eric Frentzel
William Mahan

Kyle Eastwood
Stork Club Band

Gregory Hoyt
Agent One

Jenny Phagan
Baker's Wife

Leslie Augustine
Lindbergh Nanny (uncredited)

Fileena Bahris
Starlet (uncredited)

Belinda Gosbee
Gangster's Moll (uncredited)

Elizabeth Karr
Secretary (uncredited)

Martin Luther King Jr.
Self (archive footage) (uncredited)

Pat Nixon
Self (archive footage) (uncredited)

Richard Nixon
Self (archive footage) (uncredited)

Jamie Noel
Racetrack Gambler (uncredited)

Miles Fisher
Agent Garrison

Robert Fleet
Edgar's Mother's Doctor

Scot Carlisle
Agent Williams

Ryan McPartlin
Lawrence Richey