
| Fredric March | ... | Samuel Langhorne Clemens (Mark Twain) |
 | Alexis Smith | ... | Olivia Langdon Clemens |
 | Donald Crisp | ... | J.B. Pond |
 | Alan Hale | ... | Steve Gillis |

| C. Aubrey Smith | ... | Oxford Chancellor |

| John Carradine | ... | Bret Harte |
 | William Henry | ... | Charles Langdon (as Bill Henry) |
 | Robert Barrat | ... | Horace E. Bixby, Riverboat Captain |
 | Walter Hampden | ... | Jervis Langdon |
 | Joyce Reynolds | ... | Clara Clemens |
 | Whitford Kane | ... | Joe Goodwin, Editor |
 | Percy Kilbride | ... | Billings, Enterprise Typesetter |
 | Nana Bryant | ... | Mrs. Langdon |
 | Jackie Brown | ... | Samuel Clemens - age 12 |
 | Dickie Jones | ... | Samuel Clemens - age 15 |
 | Russell Gleason | ... | Orion Clemens, Editor Habbibal Journal |
 | Joseph Crehan | ... | Riverboat Captain / Ulysses S. Grant |
 | Douglas Wood | ... | William Dean Howells |
| rest of cast listed alphabetically: |
 | Ernie Adams | ... | Pickpocket (uncredited) |
 | Gloria Ann Crawford | ... | Susie Clemens as a Child (uncredited) |
 | Hooper Atchley | ... | Secretary (uncredited) |
 | Arthur Aylesworth | ... | Worried Buffalo Merchant (uncredited) |
 | Lynn Baggett | ... | Susie Clemens (uncredited) |
 | Leah Baird | ... | Bit Role (uncredited) |

| Diana Barrymore | ... | Undetermined Role (uncredited) (unconfirmed) |
 | Willie Best | ... | George, Twain's Butler (uncredited) |
 | Henry Blair | ... | Boy (uncredited) |

| Oliver Blake | ... | Miner (uncredited) |
 | Monte Blue | ... | Captain of 'Queen of Dixie' (uncredited) |
 | Bob Burns | ... | Passenger (uncredited) |
 | Viola Callahan | ... | Bit Role (uncredited) |
 | Burr Caruth | ... | Oliver W. Holmes (uncredited) |
 | Wheaton Chambers | ... | Joker at Train Station (uncredited) |
 | Davison Clark | ... | Henry Wadsworth Longfellow (uncredited) |
 | Chester Conklin | ... | Frog Jump Contest Judge (uncredited) |
 | Carol Coombs | ... | Clara as a Child (uncredited) |
 | Lloyd Corrigan | ... | Town Citizen (uncredited) |
 | Frank Dae | ... | Houghton (uncredited) |
 | Frank Darien | ... | Toy Store Proprietor (uncredited) |
 | Earle S. Dewey | ... | Southerner (uncredited) |
 | Dudley Dickerson | ... | Black Man (uncredited) |
 | Dennis Donnelly | ... | Baby (uncredited) |
 | Roland Drew | ... | Editor (uncredited) |
 | Bill Edwards | ... | Bit Role (uncredited) |
 | Sarah Edwards | ... | Bit Role (uncredited) |
 | Dick Elliott | ... | Spectator at Frog-Jumping Contest (uncredited) |
 | Jim Farley | ... | Prospector (uncredited) |
 | Ross Ford | ... | Hardy - Howell's Secretary (uncredited) |
 | Willie Fung | ... | Chinese Man (uncredited) |
 | Rosina Galli | ... | Italian Nurse (uncredited) |
 | Jack Gardner | ... | Bit Role (uncredited) |
 | Jack Gargan | ... | Bit Role (uncredited) |
 | William Gould | ... | Ship's Bouncer (uncredited) |
 | Mildred Gover | ... | Black Woman (uncredited) |
 | Jessica Grayson | ... | Housekeeper (uncredited) |
 | William Haade | ... | Steam Room Chief (uncredited) |
 | Frank Hagney | ... | Crew Chief (uncredited) |
 | Creighton Hale | ... | Man with Mule (uncredited) |
 | Thurston Hall | ... | Politician (uncredited) |
 | George Haywood | ... | Bit Role (uncredited) |
 | Robert Herrick | ... | English Boy (uncredited) |
 | Harry Hilliard | ... | John G. Whittier (uncredited) |
 | Gene Holland | ... | Huckleberry Finn (uncredited) |
 | Harry Holman | ... | Drunken Guest (uncredited) |
 | Stuart Holmes | ... | Man at Reception (uncredited) |
 | Robert Homans | ... | Bit Role (uncredited) |
 | Olin Howland | ... | Riverboat Southerner (uncredited) |
 | George Humbert | ... | Bit Role (uncredited) |
 | Brandon Hurst | ... | Ralph Waldo Emerson (uncredited) |
 | Charles Irwin | ... | British Reporter (uncredited) |

| Kay Johnson | ... | Jane Clemens (uncredited) |
 | Payne B. Johnson | ... | Boy in Frog Jumping Scene (uncredited) |
 | Lew Kelly | ... | Pilot House Guest (uncredited) |
 | Fred Kelsey | ... | River Rafter (uncredited) |
 | Bill Kennedy | ... | Bit Role (uncredited) |
 | Victor Kilian | ... | Higgins (uncredited) |
 | Richard Kipling | ... | Bit Role (uncredited) |
 | Bobby Larson | ... | Boy (uncredited) |

| Peter Lawford | ... | Young Oxford Celebrant (uncredited) |
 | Billy Lechner | ... | English Boy (uncredited) |
 | George Lessey | ... | Henry H. Rogers, Financier (uncredited) |
 | Charles Marsh | ... | Prospector (uncredited) |
 | Frank Mayo | ... | Pilot House Guest (uncredited) |
 | Charles McAvoy | ... | Prospector (uncredited) |
 | Sam McDaniel | ... | Comet Watcher (uncredited) |
 | Sammy McKim | ... | Cub Pilot (uncredited) |
 | John 'Skins' Miller | ... | Cross-Eyed Man (uncredited) |
 | Michael Miller | ... | Tom Sawyer (uncredited) |
 | Jack Mower | ... | Pilot House Guest (uncredited) |
 | Paul Newlan | ... | Boss Deck Hand (uncredited) |
 | Frank O'Connor | ... | Carriage Driver (uncredited) |
 | Pat O'Malley | ... | Captain's Aide (uncredited) |
 | Bud Osborne | ... | Lee Griggs (uncredited) |
 | Paul Panzer | ... | Pilot House Guest (uncredited) |
 | Charles Peck | ... | English Boy (uncredited) |
 | Frank Pharr | ... | Stagecoach Passenger (uncredited) |
 | Francis Pierlot | ... | Paige - Typesetter Inventor (uncredited) |
 | Lee Powell | ... | Cowboy (uncredited) |
 | Lillian Randolph | ... | Black Woman (uncredited) |
 | George Reed | ... | Comet Watcher (uncredited) |

| Frank Reicher | ... | Doctor in Elmira, N.Y. (uncredited) |
 | Betty Roadman | ... | Bit Role (uncredited) |
 | Christian Rub | ... | Jones - Printer (uncredited) |
 | Charlene Salerno | ... | Jean as a Child (uncredited) |
 | Cliff Saum | ... | Prospector (uncredited) |
 | Francis Sayles | ... | Bit Role (uncredited) |
 | Paul Scardon | ... | Rudyard Kipling (uncredited) |
 | George Sherwood | ... | Prospector (uncredited) |
 | Emmett Smith | ... | Repeater (uncredited) |
 | Walter Soderling | ... | Telegrapher (uncredited) |
 | Frederick Spencer | ... | Jim (uncredited) |
 | Libby Taylor | ... | Black Woman (uncredited) |
 | Joyce Tucker | ... | Jean (uncredited) |
 | Harry Tyler | ... | Assistant Editor (uncredited) |
 | Dorothy Vaughan | ... | Katie Leary, Twain's Maid (uncredited) |
 | Sailor Vincent | ... | Shopkeeper (uncredited) |
 | Charles Waldron | ... | Dr. Quintard, Twain's Personal Physician (uncredited) |
 | Eddy Waller | ... | Southerner (uncredited) |
 | Lee 'Lasses' White | ... | Yokel (uncredited) |
 | Leo White | ... | Barber (uncredited) |
 | Ernest Whitman | ... | Stoker (uncredited) |
 | Frank Wilcox | ... | Judge Clemens, Samuel's Father (uncredited) |
 | Lottie Williams | ... | Lady in Audience (uncredited) |
 | Norman Willis | ... | Ben Lake (uncredited) |
 | Joan Winfield | ... | Bit Role (uncredited) |
 | Harry Woods | ... | Bixby's Depth Caller (uncredited) |
 | Harry Worth | ... | Gambler (uncredited) |
He's now been physically dead all of 95 years, but Samuel Langhorne Clemens (a.k.a. Mark Twain) is still the most popular novelist and writer in American history, and one of the few great American writers to merit his own film biography. There is no film (at the very least no remembered films) about Charles Brockden Brown (our first major novelist), Washington Irving, Fenimore Cooper (whom Twain hated reading), Hawthorne, Melville, Howells, James, Crane, Dreiser, Wharton, Alcott, Cather, Fitzgerald, Lewis, Hemingway, Faulkner, Steinbeck, Wouk, Salinger, Vonnegut, or Bellow. You have to go back to Edgar Allen Poe (the subject of several films, including a silent one (THE AVENGING CONSCIENCE) by D.W. Griffith) to find another major American writer who is a subject of biography. There is also a film on the life of Jack London made in the 1940s. But the key is that Poe, London, and Twain had interesting lives meriting filming.
The film is true in its outline but the fleshing out is questionable. For example, Twain did go into the mining fields of California and Nevada in the late 1860s, but he probably did not win the jumping frog contest that was the basis of his first literary success, "The Jumping Frog of Calaveras County". Nor was his literary rival, Francis Bret Harte (John Carridine), the man who lost that contest. But there was a contest he apparently witnessed in 1865, and he expanded on it for his classic short story.
Some aspects of the story I am surprised to find in the film. The infamous Whittier Birthday Speech fiasco (although still debated) did occur in 1876, and somehow hurt his acceptance by the eastern literati whose "gods" (Emerson, Holmes, and Longfellow) were somewhat laughed at in it. Also there is the frightening story of the Paige Typesetter that helped bankrupt Twain (forcing him to go lecturing and writing around the world in the 1890s.
The fact is, the film is actually better in presenting Twain's literary and private life than the average movie biography of that period or even now. March looks like his subject (and his make-up ages him properly). He knows how to do the delivery of the comic lectures perfectly. Note how at one point when he says to the audience, "The last time I went south....", March points quietly but prolonged downward, so the audience realizes he means "the last time I went to Hell...." We are used today to Hal Holbrook's "MARK TWAIN TONIGHT" performances, with his southern delivery, but March is just as effective in his way.
The other performances are good, with Walter Hampden lecturing March about what gentlemen of his class consider REAL literature, or with Percy Kilbride as a typesetter who trains Twain, and who later claims he helped make Clemens Mark Twain. Alexis Smith manages to portray Livy (Olivia) Twain as the perfect love match she was. The film does not hesitate to show Twain's career had as many missteps as successful peaks. It does avoid his attack on American Imperialism, and it does not detail the series of family deaths that plagued his last decade (two daughters and a nephew followed Livy to the grave before Sam followed her in 1910). But for getting the general outline correct, and for casting the film correctly and producing it very well I can say it deserves a "10" out of "10".