Margaret McGettigan was born to Daniel and Bridget E. McGettigan in Virginia in 1863. The family moved to northwest Missouri by 1870. She entered as a candidate on November 30, 1880, was invested on March 19, 1881, and made profession on May 5, 1882, receiving the name Sr. M. Pius. Her perpetual vows were made on July 28, 1887.

Sister M. Pius taught at schools in Boonville, MO and Conception, MO until 1893 when debilitating rheumatism curtailed her activity and caused her much suffering until her death on November 19, 1903 at the age of forty.