He was appointed bishop on 14 April 2000 by Pope John Paul II and was consecrated and installed on 30 July 2000.
He then studied at Mafinga Minor Seminary in the Diocese of Iringa, where he completed his secondary school education in 1978.
[1][2] Later, he graduated with a Master's degree from the Catholic University of Eastern Africa (CUEA) in Nairobi, Kenya.
[1][2][3] Pope Francis appointed him Archbishop of the Roman Catholic Archdiocese of Songea on 14 March 2014.
[1][2] As of November 2019, Bishop Damian Denis Dallu, Archbishop of Songea, served as the President of the Episcopal Commission for Missions, in Tanzania.