When Mary Kathryn Trostle was born on 7 November 1910, her father, George Washington Trostle, was 49 and her mother, Ida Belle Vanderhoof, was 35. She married John Martin Laux on 25 November 1939, in Cook, Illinois, United States. She lived in Woodbury, Cumberland, Illinois, United States in 1920. She died on 12 February 1994, in Oak Park, Cook, Illinois, United States, at the age of 83, and was buried in Chicago, Cook, Illinois, United States.