Following ordination, Fr Brendan taught mathematics and economics at St Meinrad until receiving an assignment to Immaculate Conception Mission, Stephan, South Dakota in 1941. He remained there until 1946 and was then assigned to St Ann's Indian Mission, Belcourt, North Dakota where he was stationed for a year. His next assignment was at St Paul's Indian Mission, Marty, South Dakota. In 1949 he was recalled to St Meinrad to teach at St Placid Hall where he befriended several brotherhood aspirants who would later work with him on the construction of Blue Cloud Abbey.

When the South Dakota community was founded, Fr Brendan was placed in charge of the building project. He also taught moral theology to our clerics and on weekends assisted in many parishes of the Sioux Falls Diocese and neighboring dioceses. Two years before the completion of the abbey, he was assigned to St Michael's Indian Mission at St Michael, North Dakota. His last assignment on the mission was at Marty, where he worked from 1971 until 1974. The next three years he was stationed at Mother of God Priory, Watertown, followed by an assignment as chaplain of St Ann's Hospital in Watertown, the position from which he was retired to the abbey in 1983 because of failing health.

Early in 1984 Fr Brendan suffered a stroke form which he never recovered. The last few months he was completely bedridden and uncommunicative most of the time. He died on the anniversary of the dedication of the Blue Cloud Abbey Church, an appropriate feast for a man who had overseen the construction of our buildings.

Fr Brendan could be stubborn and unyielding, as insuperable as the Great Skelling Rock off the coast of the island where his ancestors and his patronal saint lived. He enjoyed arguing for the sake of an argument and could easily dismiss you with an adamant "Piffle!" Yet, he was also a gracious and mellow person. This was only natural for someone born of parents named Patrick and Bridget Keane.