Upon completion of the Novitiate in 1873, at age 47, Brother Brendan was assigned to primary school classes at the Brothers' school in St. Louis, Missouri, to begin his teaching career. He later taught in Santa Fe, New Mexico: Kansas City, Missouri: and Feehanville, Illinois, completing his teaching career at St. Malachi School in St. Louis. In 1896 he entered the retirement "Community of the Ancients" at Glencoe, Missouri, where he later died on January 28, 1903, at age seventy-seven and in his thirtieth year as a De La Salle Christian Brother.