Born in Louisville, Kentucky, on September 25, 1902, Agnes was the daughter of Gustave and Elizabeth Hemberger Kastner. She attended grade school at St. James School and high school at Ursuline Academy, both in Louisville, and received her music education at the Louisville Conservatory of Music. Agnes then became organist at St. James Catholic Church. At the age of 24, she entered the novitiate at Mount Saint Joseph and during these months she taught harmony to the Sisters in the novitiate. Agnes received the Ursuline habit and the name Sister Agnes Therese on March 19, 1927.
Well-prepared for the music teaching apostolate, Sister Agnes Therese was assigned to St. Columba in Louisville in 1928 through 1934. She then spent one year teaching at Seven Holy Founders in Affton, Missouri, and studied at Webster Groves College in Webster Groves. She returned to Louisville and taught at St. Paul and St. Columba. From 1948 to 1958, she was assigned to St. Thomas More in Paducah, Kentucky. She returned to Louisville and was assigned to St. Angela Home and St. Columba. In 1967, she returned for two years to St. Thomas More in Paducah. Her final teaching assignment was to St. Denis in Shively, Kentucky.
She retired to the Motherhouse in January 1975 suffering from a serious heart condition. She died October 25, 1977. Father Anthony Ziegler, chaplain, Msgr. Edward Russell and Msgr. Bernard Powers celebrated the funeral Mass October 29, 1977. Sister Agnes Therese’s remains are buried in the convent cemetery.