Born on January 23, 1838 in Heppenheim, in the Grand Duchy of Hesse, Maria Anna Barbara Koob moved with her family the next year to Utica, New York. Her father became an invalid when Maria was in the eighth grade. She left school and worked in a factory to help support her family. By 1862 her younger siblings were old enough to take care of themselves, and she felt free to follow her heart’s desire by joining the Sisters of the Third Order Regulars of Saint Francis based in Syracuse, New York. After her novitiate, she served as a teacher and principal in the parochial schools set up for the children of German-speaking immigrants.
She rapidly showed leadership and organizational skills and from 1870-1877 ran Saint Joseph’s Hospital in Syracuse. In 1883, by which time she was Superior General of her congregation, she received a plea for sisters to provide medical assistance to the leper colony on Molokai in Hawaii from the King of Hawaii. Fifty religious institutes had turned down the King, but he struck paydirt with the fifty-first. Mother Marianne responded enthusiastically, and she and six of her sisters landed in Honolulu on November 8, 1883. The sisters took charge of Kakako Branch Hospital which served as a receiving hospital for lepers from all over Hawaii, with the most serious cases sent to Molokai. The next year Mother Marianne, at the request of the Hawaiian government, set up Malulani Hospital, the first general hospital on Maui.