James Stewart as Jefferson Smith

Jean Arthur as Clarissa Saunders

Claude Rains as Joseph Paine

Edward Arnold as Jim Taylor

Guy Kibbee as Governor Hopper

Thomas Mitchell as Diz Moore

Eugene Pallette as Chick McGann

Beulah Bondi as Ma Smith

H.B. Warner as Senate Majority Leader

Harry Carey as President of the Senate

Astrid Allwyn as Susan Paine

Ruth Donnelly as Emma Hopper

Grant Mitchell as Senator MacPherson

Porter Hall as Senator Monroe

Pierre Watkin as Senator Barnes

Charles Lane as Nosey

William Demarest as Bill Griffith

Dick Elliott as Carl Cook

Billy Watson as Peter Hopper

Delmar Watson as Jimmie Hopper

John Russell as Hopper Boy

Harry Watson as Hopper Boy

Garry Watson as Hopper Boy

Larry Simms as Hopper Boy

H.V. Kaltenborn as Radio Broadcaster

Russell Simpson as Kenneth Allen (uncredited)

Frances Gifford as Hopper Girl (uncredited)

Colin James Mackey as Narrator (uncredited)

Wilson Benge as Hopper's Butler (uncredited)

Dickie Jones as Richard Jones (uncredited)

Erville Alderson as Handwriting Expert (uncredited)

Frank Puglia as Handwriting Expert (uncredited)

Maurice Cass as Handwriting Expert (uncredited)

Stanley Andrews as Senator Hodges (uncredited)

Al Bridge as Senator Dwight (uncredited)

Edwin August as Senator (uncredited)

Edmund Cobb as Senator Gower (uncredited)

Sam Ash as Senator Lancaster (uncredited)

Harry A. Bailey as Senator Hammett (uncredited)

Stanley Mack as Senator (uncredited)

Brooks Benedict as Senate Clerk (uncredited)

Wade Boteler as Family Man (uncredited)

Dorothy Comingore as Woman at Station (uncredited)

Chester Conklin as Reporter (uncredited)

Gino Corrado as Barber (uncredited)

Ann Doran as Paine's Secretary (uncredited)

Robert Emmett Keane as Editor (uncredited)

Matt McHugh as Reporter (uncredited)

Kathryn Bates as Committeewoman (uncredited)

Frank Austin as Inventor (uncredited)

William Arnold as Reporter (uncredited)

Tommy Baker as Boy Ranger (uncredited)

Robert Sterling as Senate Reporter (uncredited)

Dub Taylor as Reporter (uncredited)

George Chandler as Reporter (uncredited)

Fred 'Snowflake' Toones as Porter (uncredited)

Jack Carson as Sweeney Farrell (uncredited)

Tommy Bupp as Cheering Boy (uncredited)

Dora Clement as Mrs. McGann (uncredited)

Bert Moorhouse as Man in Senate Building (uncredited)

Harry C. Bradley as Arthur Kim (uncredited)

Lynton Brent as Photographer (uncredited)

Ed Brewer as Senate Reporter (uncredited)

Harlan Briggs as Mr. Edwards (uncredited)

Harry Burkhardt as Senate Reporter (uncredited)

Frederick Burton as Senator Dearhorn (uncredited)

Georgia Caine as Third Radio Speaker (uncredited)

Ken Carpenter as Announcer (uncredited)

Burr Caruth as Townsend (uncredited)

Allan Cavan as Ragner (uncredited)

Eddy Chandler as Reporter (uncredited)

Davison Clark as Committeeman (uncredited)

Richard Clucas as (uncredited)

Shirley Coates as Assistant Bartender (uncredited)

Eddie Coke as Photographer (uncredited)

Hal Cooke as Reporter (uncredited)

Alec Craig as Speaker (uncredited)

Anne Cornwall as Senate Reporter (uncredited)

George Cooper as Waiter (uncredited)

Georgie Cooper as Committeewoman (uncredited)

Jack Cooper as Photographer (uncredited)

Nick Copeland as Senate Reporter (uncredited)

Vernon Dent as Senate Reporter (uncredited)

Maurice Costello as Diggs (uncredited)

Beatrice Curtis as Paine's Secretary (uncredited)

Lew Davis as Senate Clerk (uncredited)

Dulcie Day as Senate Reporter (uncredited)

Wally Dean as Paine's Friend (uncredited)

Harry Depp as Hat Salesman / Secretary (uncredited)

Byron Foulger as Hopper's Secretary (uncredited)

Helen Jerome Eddy as Paine's Secretary (uncredited)

Douglas Evans as Francis Scott Key (uncredited)

Joe Devlin as Waiter (uncredited)

Clyde Dilson as Reporter (uncredited)

John Dilson as Secretary (uncredited)

Neal Dodd as Senate Chaplain (uncredited)

Lester Dorr as Taylor's Stooge (uncredited)

Robert Dudley as Reporter (uncredited)

Edward Earle as Reporter (uncredited)

Jack Egan as Reporter (uncredited)

Eddie Fetherston as Senate Reporter (uncredited)

Mabel Forrest as Senate Reporter (uncredited)

Gladys Gale as Committeewoman (uncredited)

Jack Gardner as Reporter (uncredited)

Mary Gordon as Woman (uncredited)

June Gittelson as Woman at Station (uncredited)

Lorna Gray as Woman at Station (uncredited)

Harry Hayden as First Radio Announcer (uncredited)

Louis Jean Heydt as Soapbox Speaker (uncredited)

John Ince as Senator Fernwick (uncredited)

Frank Jaquet as Senator Byron (uncredited)

Philo McCullough as Senator Albert (uncredited)

Wright Kramer as Senator Carlton (uncredited)

Henry Hebert as Senator (uncredited)

Fred Hoose as Senator (uncredited)

Richard Kipling as Senator (uncredited)

Roger Haliday as Senate Guard (uncredited)

Wilfred Hari as House Boy (uncredited)

Philip Hurlic as Boy Ranger (uncredited)

Olaf Hytten as Butler (uncredited)

Lloyd Ingraham as Committeeman (uncredited)

Mitchell Ingraham as (uncredited)

Dick Jensen as Hoodlum (uncredited)

John Lester Johnson as Butler (uncredited)

Eddie Kane as Reporter (uncredited)

Donald Kerr as Reporter (uncredited)

Milton Kibbee as Senate Reporter (uncredited)

Joe King as Summers (uncredited)

Evalyn Knapp as Reporter (uncredited)

Paul Kruger as Bodyguard (uncredited)

Bobby Larson as Boy Ranger (uncredited)

Billy Lechner as Boy Ranger (uncredited)

Jackie Lowe as Boy Ranger (uncredited)

P.H. Levy as Rabbi (uncredited)

Vera Lewis as Mrs. Edwards (uncredited)

Jack Lindquist as Chorus Member (uncredited)

George Lloyd as Hoodlum (uncredited)

Arthur Loft as Chief Clerk (uncredited)

Jack Low as Hoodlum (uncredited)

Jimmie Lucas as Photographer (uncredited)

Mary MacLaren as Head Sister (uncredited)

Hank Mann as Photographer (uncredited)

Margaret Mann as Nun (uncredited)

Eric Mayne as Man in Senate Building (uncredited)

Ralph McCullough as Assistant Bartender (uncredited)

George McKay as Reporter (uncredited)

Lafe McKee as Veteran at Lincoln Memorial (uncredited)

Ben Taggart as Pompous Man (uncredited)

Field Norton as Pompous Man (uncredited)

Wilfred Lucas as Pompous Man (uncredited)

Sammy McKim as Boy Ranger (uncredited)

James McNamara as Reporter (uncredited)

William Newell as Reporter (uncredited)

Robert Middlemass as Radio Announcer #2 (uncredited)

James Millican as Senate Reporter (uncredited)

Howard M. Mitchell as Shoe Salesman (uncredited)

Charles R. Moore as Porter (uncredited)

Gene Morgan as Reporter (uncredited)

Robert Morgan as Senate Clerk (uncredited)

Ray Nichols as Boy Ranger (uncredited)

Alex Novinsky as Foreign Diplomat (uncredited)

Frank O'Connor as Senator Alfred (uncredited)

Frank Otto as Fisk (uncredited)

Joe Palma as Hoodlum (uncredited)

Spencer Quinn as (uncredited)

Tom Quinn as Senate Reporter (uncredited)

Ed Randolph as Senate Reporter (uncredited)

Charles Regan as Hoodlum (uncredited)

Jack Rice as Lang (uncredited)

Wyndham Standing as Senator Ashman (uncredited)

Ferris Taylor as Senator Carlisle (uncredited)

Jack Richardson as Senator Manchester (uncredited)

Walter Soderling as Senator Pickett (uncredited)

Harry Stafford as Senator Atwater (uncredited)

Victor Travis as Senator Grainger (uncredited)

Carl Stockdale as Senator Burdette (uncredited)

Bob Walker as Senator Holland (uncredited)

Henry Roquemore as Senator (uncredited)

Craig Stevens as Senate Reporter (uncredited)

Paul Stanton as Flood a Newsman (uncredited)

Johnny Russell as Otis Hopper (uncredited)

Walter Sande as Newspaperman with Pipe (uncredited)

Frank M. Thomas as Hendricks (uncredited)

Harry Strang as Bodyguard (uncredited)

Harry Tenbrook as Bodyguard (uncredited)

Dave Willock as Senate Guard (uncredited)

Lloyd Whitlock as Schultz (uncredited)

John Tyrrell as (uncredited)

Frederick Vroom as Paine's Friend (uncredited)

Charles Sullivan as Cab Driver (uncredited)

Arthur Thalasso as Doorman (uncredited)

Edward Thomas as Butler (uncredited)

Laura Treadwell as Mrs. Taylor (uncredited)

Layne Tom Jr. as Boy Ranger (uncredited)

Myonne Walsh as Jane Hopper (uncredited)

Billy Wayne as Reporter (uncredited)

Max Waizmann as Photographer (uncredited)

John Ward as Photographer (uncredited)

Jane Loofbourrow as Committeewoman (uncredited)

Blanche Payson as Committeewoman (uncredited)

Emma Tansey as Committeewoman (uncredited)

Bess Wade as Committeewoman (uncredited)

Florence Wix as Committeewoman (uncredited)

Eleanor Wood as Committeewoman (uncredited)

Jesse Graves as Black Committeeman (uncredited)

Gus Glassmire as Angry Committee Member (uncredited)

Larry Steers as Committeeman (uncredited)

Landers Stevens as Committeeman (uncredited)

William Worthington as Committeeman (uncredited)

Edward Biby as Foreign Diplomat (uncredited)

Count Stefenelli as Foreign Diplomat (uncredited)

David Wade as (uncredited)

Frank McLure as Senator (uncredited)