After his release from prison in 1920, Mun taught history at Jung-dong, Jung-ang, Baejae, and Songdo schools, and contributed articles on history to the Chosun Ilbo, Jung-wae Ilbo, and Kaebyeok, to increase national attention to history.
In April 1933 he became an editor of the Chosun Ilbo and focused on the popularization of history.