Damasceno Assis was born 15 February 1937 in Capela Nova.

In 1955, he entered the Minor Seminary of the archdiocese of Mariana, where he did his secondary studies and then the Major Seminary, where he studied philosophy. In 1960, Archbishop Oscar de Oliveira, of Mariana, sent him to the newly established archdiocese of Brasília, as a help to that new local church, inaugurated on 21 April of that same year. In 1961, Brasília’s archbishop, sent him to Rome to study theology at the Pontifical Gregorian University, where he obtained a licentiate. He resided at Colegio Pio Brasileiro during those years, the Second Vatican Council was occurring. In 1965, he was sent to Germany, where he concluded his formation at the Superior Institute of Catechesis in Münich.

He was ordained a priest on 19 March 1968, in Conselheiro Lafaiete, by José Newton de Almeida Baptista, archbishop of Brasília. In the archdiocese of Brasília, he served as coordinator of catechesis and pastor of the parish of Santíssimo Sacramento. He also served as chancellor and was co-founder and professor of the Major Seminary Nossa Senhora de Fatima and at the same time professor in the Department of Philosophy of the University of Brasília.

He was appointed Titular Bishop of Nova Petra and auxiliary bishop of Brasília on 18 June 1986. Promoted metropolitan archbishop of Aparecida 28 January 2004. In 2007, he was elected president of the Episcopal Council of Latin America (CELAM), his presidency ended in 2011. Benedict XVI created him Cardinal-Priest of Immacolata al Tiburtino in the consistory of 20 November 2010. In 2011, he was elected president of the National Conference of Bishops of Brazil (Confêrencia Nacional dos Bispos do Brasil) for a quadrennium.