The narration describes Al Jolson as one of America's leading vaudevillians. Jolson never played vaudeville; he went directly from performing in minstrel shows to appearing in Broadway musicals.
This film repeats the mistake from the 1999 documentary "Yours for a Song: The Women of Tin Pan Alley" that claimed Dorothy Fields was the first woman to break through male-dominated Broadway and write the lyrics for a hit musical. Before Fields, Rida Johnson Young had written "The Naughty Marietta" with Victor Herbert and Dorothy Donnelly had written "The Student Prince" with Sigmund Romberg. (Both Herbert and Romberg are mentioned in this show, but their female collaborators aren't.)