She converted her house in Pompton, New Jersey into the Henry C. deMille Preparatory School for Girls.

[3] In 1900, Beatrice deMille collaborated with Harriet Ford to write her first published play "The Greatest Thing in The World" – directed by Liebler & Company, and performed on Broadway and in Washington DC.

[3] Beatrice was a deal maker and she introduced her son to Jesse Lasky and his production grew to be Paramount Pictures.

She moved to California in 1914 and she is credited with launching the careers of actor Victor Moore who appeared in her son's films and screenwriter Beulah Marie Dix.

[3] Over the next few years she wrote a fair number of screen plays which were made into silent films.