Errors in geography: There are no mountains visible from Providence, RI, despite what is shown in the opening scene.
Boom mic visible: Shadow sweeping across the set during "Yankee Doodle Dandy".
Boom mic visible: Shadow sweeping across set during "I'd rather be right" after Cohan steps off the stairs and is behind the long table.
Anachronisms: In the "You're A Grand Old Flag" number, which supposedly takes place in the 1906 production of "George Washington Jr.," we see a group of Boy Scous march onto the stage. The Scout Movement was founded in 1907 by Robert Baden-Powell in England and wasn't founded in the United States until 1910.
Anachronisms: The "You're A Grand Old Flag" number, supposedly takes place in the 1906 production of "George Washington Jr.," and uses multiple period flags to represent times before 1906. The Civil War flag, as an example, is correct for the time in question. However, in the final sequence characters carry, and an soft screen projection is made of, multiple 48 star flags. The 48 star flag was not introduced until 1912. In 1906, it should have been a 45 star flag.
Continuity: In the dressing room scene, just before Albee's visit, Jerry Cohan wraps a scarf around his neck while he's talking to George and leaves one end outside of his dressing gown. In the next shot, the scarf is tucked in.
Factual errors: Variety newspaper headline is actually "Sticks Nix Hick Pix" (17 July 1935).
Factual errors: In a newspaper photograph, the Lusitania has two funnels instead of four.
Continuity: After George plays the violin as a child, he sets the instrument down on a table and it changes position between shots.
Factual errors: Cohan received a Congressional Gold Medal, not the Congressional Medal of Honor.
Anachronisms: The writers stretch the bounds "poetic license" by trying to tie George M Cohan's flop Popularity (1906) with the sinking of the Lusitania (1915) and the U.S. entry into World War I (1917) as all occurring at the same time.
Anachronisms: The song "Beat Me Daddy, Eight to the Bar" is referenced before Cohan starred in the 1937 production of "I'd Rather Be Right Than Be President". The song was written in 1940.
Anachronisms: The violin George played on stage as a child was fitted with a chin piece not used on violins until the twentieth century.
Anachronisms: In the "You're A Grand Old Flag" number, which supposedly takes place in the 1906 production of "George Washington Jr.," an African-American chorus pays tribute to a backdrop image of Abraham Lincoln, seated in a chair. The Lincoln image is taken from Daniel Chester French's sculpture for the Lincoln Memorial. This sculpture was not completed until the opening of the Lincoln Memorial in 1922.
Factual errors: When George arrives at the White House he walks up a set of stairs to reach the oval office. At the end of the movie, he dances down the same flight of stairs. The oval office is in the West Wing and on the ground floor.
Boom mic visible: The boom mic's shadow falls across the back wall as Cohan and Harris head to the Western Union office.
Continuity: George's work coat is unbuttoned/unbuttoned during the scene where he is chopping wood, and talking to his sister.
Factual errors: After Cohan's father, Jerry, dies, George is called the last of the Four Cohans. Actually, Cohan's mother, Helen, died in 1928. Jerry died in 1917 and Cohan's sister, Josie, died in 1916.
Anachronisms: Near the beginning of the movie, Cohan is describing his birth (in 1878) to FDR, and speaks of the flag "having fewer stars then, but people knew more were coming". The camera fades to a scene of an American flag waving on a flagpole, before panning down to people at a 4th of July parade waving hand held flags. The hand held flags appear to be the correct 38 star flags of 1878, but the flag on the pole is the 45 star flag introduced in 1896.
Factual errors: Despite the film's storyline, and Cohan's own lifelong claim, that he was born on the 4th of July (and his having written the song "Yankee Doodle Dandy" containing that very line), George M. Cohan was in fact born on the 3rd of July (1878).
Factual errors: In the movie, Josie was younger than George. Josie was was actually two years older than George.