She was born on July 6, 1921, in Roebling, New Jersey, to Jacob and Anna Lockett Lawrence. She was the wife of Elmer R. Leaver from 1940 until his death in 1977.
She was a former resident of Sacramento, California, and Roebling, New Jersey. In 1971 she became one of Jehovah's Witnesses, and dedicated her life to helping others learn about God and the Bible.
Mary is survived by her brother, William W. Lawrence of Springfield, Pennsylvania, her son William R. Leaver, and her grandchildren. Her sister, Helen Bancroft of Philadelphia, passed away in 2009.
A memorial service will be held at the Lacey, Washington, Kingdom Hall of Jehovah's Witnesses, date and time to be announced.