[3] At the age of sixteen, he joined the People's Security Army during the Indonesian National Revolution and was shocked by the way the troops treated the villagers.

[2] In 1950, upon hearing a speech about the harmful effects of the revolution on civilians by one of the commanders, Major Isman, he decided to serve as a priest.

[6] He had also set up an explorative elementary school for the community that was displaced by the development of the Kedung Ombo reservoir in Central Java, as well as the poor in the Code River, Yogyakarta.

[9] According to Erwinthon P. Napitupulu, the author of a book on Mangunwijaya, due to be published at the end of 2011, Mangun heads the list of the top 10 Indonesian architects.

[9] Romo Mangun's dedication to helping those who were poor,[10] oppressed and marginalised by politics through an "outcry of the voice of conscience" made him a strong opponent of the Soeharto regime.