Factual error: When the Yankees play Boston, a dirt path is visible going from home to the pitcher's mound. Fenway Park, where the Red Sox play, has never had such a thing.
Factual error: Although quite typical for biopics of this era, certain aspects of Cohan's life are glossed over. The movie shows him in a lifelong marriage to his first love. However, he was in fact married in 1899 to Ethel Levy, and after their divorce in 1907 he married Agnes Mary Nolan, who remained his wife until Cohan's death in 1942.