- Jean Arthur
- Saunders
- James Stewart
- Jefferson Smith
- Claude Rains
- Senator Joseph Paine
- Edward Arnold
- Jim Taylor
- Guy Kibbee
- Governor Hopper
- Thomas Mitchell
- Diz Moore
- Eugene Pallette
- Chick McGann
- Beulah Bondi
- Ma Smith
- H.B. Warner
- Senate Majority Leader
- Harry Carey
- President of the Senate
- Astrid Allwyn
- Susan Paine
- Ruth Donnelly
- Mrs. Hopper
- Grant Mitchell
- Senator MacPherson
- Porter Hall
- Senator Monroe
- H.V. Kaltenborn
- H.V. Kaltenborn
- Charles Lane
- Nosey
- Pierre Watkin
- Senate Minority Leader
- Dick Elliott
- Carl Cook
- William Demarest
- Bill Griffith
- Billy Watson
- Hopper Boy
- Delmar Watson
- Hopper Boy
- Harry Watson
- Hopper Boy
- Larry Simms
- Hopper Boy
- Garry Watson
- Hopper Boy
- Erville Alderson
- Handwriting Expert
- Harry Anderson
- Hoodlum
- Stanley Andrews
- Senator Hodges
- William Arnold
- Reporter
- Sam Ash
- Senator Lancaster
- Edwin August
- Senator
- Frank Austin
- Inventor at Smith's Office Door
- Harry A. Bailey
- Senator Hammett
- Tommy Baker
- Boy Ranger
- Kathryn Bates
- Committeewoman
- Brooks Benedict
- Senate Clerk
- Wilson Benge
- Hopper's Butler
- Edward Biby
- Foreign Diplomat
- Wade Boteler
- Family Man
- Harry C. Bradley
- Arthur Kim
- Lynton Brent
- Photographer
- Ed Brewer
- Senate Reporter
- Al Bridge
- Senator Dwight
- Harlan Briggs
- Mr. Edwards - Howling Citizen
- Edward Brophy
- Newspaper Employee
- Tommy Bupp
- Boy Cheering for Smith in Meeting
- Harry Burkhardt
- Senate Reporter
- Frederick Burton
- Senator Dearhorn
- Georgia Caine
- Third Radio Speaker
- Ken Carpenter
- Announcer
- Jack Carson
- Sweeney Farrell - Newsman
- Burr Caruth
- Townsend
- Maurice Cass
- Handwriting Expert
- Allan Cavan
- Ragner - Newsman
- Eddy Chandler
- Reporter
- George Chandler
- Reporter
- Davison Clark
- Committeeman
- Dora Clement
- Mrs. McGann
- Richard Clucas
- Minor Role
- Shirley Coates
- Assistant Bartender
- Edmund Cobb
- Senator Gower
- Eddie Coke
- Photographer
- Dorothy Comingore
- Woman at Station
- Chester Conklin
- Man in Press Section of Senate Gallery
- Hal Cooke
- Reporter
- George Cooper
- Waiter
- Georgie Cooper
- Committeewoman
- Jack Cooper
- Photographer
- Nick Copeland
- Senate Reporter
- Anne Cornwall
- Senate Reporter
- Gino Corrado
- Barber
- Maurice Costello
- Diggs - Newsman
- Alec Craig
- Speaker
- Beatrice Curtis
- Paine's Secretary
- Lew Davis
- Senate Clerk
- Dulce Day
- Senate Reporter
- Wally Dean
- Paine's Friend
- Vernon Dent
- Senate Reporter
- Harry Depp
- Hat Salesman / Secretary (uncredited)
- Joe Devlin
- Waiter
- Clyde Dilson
- Reporter
- John Dilson
- Secretary
- Neal Dodd
- Senate Chaplain
- Ann Doran
- Paine's Secretary
- Lester Dorr
- Taylor's Stooge
- Robert Dudley
- Reporter
- Edward Earle
- Reporter
- Helen Jerome Eddy
- Paine's Secretary
- Jack Egan
- Reporter
- Douglas Evans
- Francis Scott Key
- Eddie Fetherston
- Senate Reporter
- Mabel Forrest
- Senate Reporter
- Byron Foulger
- Hopper's Secretary
- Gladys Gale
- Committeewoman
- Jack Gardner
- Reporter
- Frances Gifford
- Hopper Girl
- June Gittelson
- Woman at Station
- Gus Glassmire
- Angry Committee Member
- Mary Gordon
- Woman
- Jesse Graves
- Black Committeeman
- Lorna Gray
- Woman at Station
- Roger Haliday
- Senate Guard
- Cliff Hall
- Senator in Final Scene
- Wilfred Hari
- House Boy
- Harry Hayden
- First Radio Announcer
- Henry Hebert
- Senator
- Louis Jean Heydt
- Soapbox Speaker
- Fred Hoose
- Senator
- Philip Hurlic
- Boy Ranger
- Olaf Hytten
- Butler
- John Ince
- Senator Fernwick
- Lloyd Ingraham
- Committeeman
- Mitchell Ingraham
- Minor Role
- Frank Jaquet
- Senator Byron
- Dick Jensen
- Hoodlum
- John Lester Johnson
- Butler
- Dickie Jones
- Pageboy Richard Jones
- Eddie Kane
- Reporter
- Robert Emmett Keane
- Editor
- Donald Kerr
- Reporter
- Milton Kibbee
- Senate Reporter
- Joe King
- Summers - Newsman
- Richard Kipling
- Senator
- Evalyn Knapp
- Reporter Asking 'What Do You Think of the Girls in This Town?'
- Wright Kramer
- Senator Carlton
- Paul Kruger
- Bodyguard
- Bobby Larson
- Boy Ranger
- Billy Lechner
- Boy Ranger
- P.H. Levy
- Rabbi
- Vera Lewis
- Mrs. Edwards
- Jack Lindquist
- Chorus Member
- George Lloyd
- Hoodlum
- Arthur Loft
- Chief Clerk
- Jane Loofbourrow
- Committeewoman
- Jack Low
- Hoodlum
- Jackie Lowe
- Boy Ranger
- Jimmie Lucas
- Photographer
- Wilfred Lucas
- Pompous Man
- Stanley Mack
- Senator
- Mary MacLaren
- Head Sister
- Hank Mann
- Photographer
- Margaret Mann
- Nun with Cheering Orphan Boys
- Thomas Martin
- Reporter
- Eric Mayne
- Man in Senate Building
- Philo McCullough
- Senator Albert
- Ralph McCullough
- Assistant Bartender
- Matt McHugh
- Reporter
- George McKay
- Reporter
- Lafe McKee
- Civil War Veteran at Lincoln Memorial
- Sammy McKim
- Boy Ranger
- Frank McLure
- Senator
- James McNamara
- Reporter
- Robert Middlemass
- Second Radio Announcer
- James Millican
- Senate Reporter
- Howard M. Mitchell
- Shoe Salesman
- Charles R. Moore
- Porter
- Bert Moorhouse
- Man in Senate Building
- Gene Morgan
- Reporter
- Robert Morgan
- Senate Clerk
- Edmund Mortimer
- Senator Fuller
- William Newell
- Reporter
- Ray Nichols
- Boy Ranger
- Field Norton
- Pompous Man
- Alex Novinsky
- Foreign Diplomat
- Frank O'Connor
- Senator Alfred
- Frank Otto
- Fisk
- Joe Palma
- Hoodlum
- Blanche Payson
- Committeewoman
- Frank Puglia
- Handwriting Expert
- Spencer Quinn
- Minor Role
- Tom Quinn
- Senate Reporter
- Ed Randolph
- Senate Reporter
- Charles Regan
- Hoodlum
- Jack Rice
- Lang
- Jack Richardson
- Senator Manchester
- Henry Roquemore
- Senator
- Johnny Russell
- Otis Hopper
- Walter Sande
- Newspaperman with Pipe
- Russell Simpson
- Kenneth Allen
- Walter Soderling
- Senator Pickett
- Harry Stafford
- Senator Atwater
- Wyndham Standing
- Senator Ashman
- Paul Stanton
- Flood - Newsman
- Larry Steers
- Committeeman
- Count Stefenelli
- Foreign Diplomat
- Robert Sterling
- Senate Reporter
- Craig Stevens
- Senate Reporter
- Landers Stevens
- Committeeman
- Carl Stockdale
- Senator Burdette
- Harry Strang
- Bodyguard
- Charles Sullivan
- Cab Driver
- Ben Taggart
- Pompous Man
- Emma Tansey
- Committeewoman
- Dub Taylor
- Reporter
- Ferris Taylor
- Senator Carlisle
- Harry Tenbrook
- Bodyguard
- Arthur Thalasso
- Doorman
- Edward Thomas
- Butler
- Frank M. Thomas
- Hendricks
- Layne Tom Jr.
- Boy Ranger
- Fred 'Snowflake' Toones
- Porter
- Victor Travis
- Senator Grainger
- Laura Treadwell
- Mrs. Taylor
- John Tyrrell
- Undetermined Role
- Frederick Vroom
- Paine's Friend
- Bess Wade
- Committeewoman
- David Wade
- Minor Role
- Max Waizmann
- Photographer
- Robert Walker
- Senator Holland
- Myonne Walsh
- Jane Hopper
- John Ward
- Photographer
- Billy Wayne
- Reporter
- Lloyd Whitlock
- Schultz - Newsman
- Dave Willock
- Senate Guard
- Florence Wix
- Committeewoman
- Eleanor Wood
- Committeewoman
- William Worthington
- Committeeman
