Lewis Stone (The Cardinal) previously played Rudolf Rassendyll and King Rudolf V of Ruritania in The Prisoner of Zenda (1922).
This version's music score is an adaptation of the one composed by Alfred Newman for the 1937 version.
The film used the same basic script that was written for the 1937 David O. Selznick film version, Il prigioniero di Zenda (1937), with Ronald Colman and Madeleine Carroll. Although many scenes and camera set-ups are exactly the same, there are a few notable differences - for example, the servant who is made to drink the drugged wine is now a woman. Also, although both John Balderstone and Wells Root retain their writing credit from the 1937 film, there is none for Donald Ogden Stewart, who was originally credited with "additional dialogue"; Stewart had, in the interim years, been blacklisted.
When Rupert of Hentzau compares Antoinette de Mauban to Florence Nightingale and recites that rhyming couplet, he is quoting Sir Walter Scott.
The Ruritanian Royal Train seen briefly as Rassendyl and the others travel to Strelsau for the coronation is stock footage of the Salzkammergut Lokalbahn, a narrow-gauge railway in the Salzburg area of Austria, that closed in 1957.