Watch on SFlix. The Unknown Soldier is a 1926 American silent drama film directed by Renaud Hoffman and written by Richard Schayer and James J. Tynan. The film stars Charles Emmett Mack, Marguerite De La Motte, Henry B. Walthall, Claire McDowell, and George Cooper. The film was released on May 30, 1926, by Producers Distributing Corporation.