Duffy was born to Alfred and Grace Yahnke in Buffalo Center, Iowa on September 19, 1927 and passed away on January 18, 2023 in Baton Rouge, Louisiana. She graduated from Buffalo Center High in 1945 and from the Mounds-Midway School of Nursing in St. Paul, Minnesota in 1948. While employed at the Iowa State University Hospital in Ames, Iowa she met her future husband, Donald E. Johnson. They were married in June, 1951, in Baton Rouge, where Don became employed as a chemist at Ethyl Corp. They made Baton Rouge their home and raised their family there. She is survived by her son, Jeff, and his wife, Meg, and their children, Noel and Christian, and son, Bruce, all of Baton Rouge. She is also survived by her brother, Larry Yahnke, and his family of Cedar Falls, Iowa. She was preceded in death by her husband, Don, her parents, Alfred and Grace Yahnke and her brothers, Ronald Yahnke and Harold (Heddy) Yahnke.
According to her wishes, she will be cremated and there will be no formal services.