Gaukler was born in Roberts County, South Dakota, United States on 13 June 1910 as one of 10 children born to German immigrants Joseph and Barbara (née Funk) Gaukler. One of her brothers, Otto, died in infancy. She moved with her family to Red Deer, Alberta, Canada, in 1930, and on 2 February 1940, joined the Daughters of Wisdom and became a nun, taking her vows in Ottawa. Her religious name was Sister Rosalie.

Gaukler was a teacher in Red Deer, and later taught in Castor and Ponoka, both in Alberta. She retired in 1974, but still occasionally worked as an aide. She also served in her congregation’s missions all across Alberta. She never married and had no children. In 2004, aged 94, she moved into a nursing home.

Gaukler outlived all of her siblings. She became the oldest person in Alberta following the 23 June 2020 death of Margherita Buttiri aged 112. She died on 19 November 2020 at the age of 110 years, 159 days, and is among the top 10 oldest known people to die in Alberta.