Mitchell was born in Pentwater, Michigan, USA, on 25 November 1904. She grew up on a farm in Pentwater with four siblings. After high school, she attended Ferris Institute (present-day Ferris State University). After obtaining her business degree, she moved to California in 1922 to care for her brother, who had sustained an injury in World War I. She moved there aboard the El Capitan passenger train.

In California, she secured a job with AT&T as a secretarial assistant. During her time there, she met her future husband, Howard Mitchell. The couple had one daughter, Suzanne, and the family settled in San Marino. Mitchell and her husband were founding members of a club in Newport Beach, a social organization that met monthly and offered numerous activities. They were also involved in the Presbyterian church. Her husband passed away in 2000, at the age of 97, after 67 years of marriage.

In 2012, she moved into the Turtle Rock assisted living home. Just before her 110th birthday, her daughter attributed her mother’s longevity to embracing a stress-free lifestyle. On her 110th birthday, her youngest sibling, Maxine Baker, was still alive at the age of 94. Mitchell’s daughter commented that one of the factors contributing to their longevity was their daily exposure to clean air. They also consumed food sourced from the land and their gardens, maintaining a diet free of hormones and pesticides. At the time, she had three grandchildren and one great-grandchild.

Mitchell passed away of natural causes in Irvine, California, USA, on 11 July 2015, at the age of 110 years, 228 days.