A Trappist monk of the Abbey of Gethsemani, Kentucky, he was an accomplished organist, liturgist, historian, and a scholar of chant and Cistercian liturgy.
On August 2, 1950, he entered the novitiate at the Trappist Abbey of Our Lady of Gethsemani and made solemn vows there on November 1, 1955; his name in religion was Chrysogonus.
He contributed intensely to his abbey's liturgical reforms after the Second Vatican Council, translating many texts from Latin into English.
He was a member of the International Commission on English in the Liturgy (ICEL) and a sought-after speaker at conferences in the USA and abroad.
[5] Waddell's a cappella choral piece “Rosa Mystica”, sung by the University of Notre Dame Folk Choir, is featured in the final scene of the film “Lady Bird”.