January 17, 1842 - June 27, 1844
(April 9, 1818 in Lima, New York – December 17, 1913 in Minersville, Utah). Claimed that Smith had a private conversation with her in 1831 when she was twelve years old,
"[At age 12 in 1831], [Smith] told me about his great vision concerning me. He said I was the first woman God commanded him to take as a plural wife. ... In 1834 he was commanded to take me for a Wife .... [In 1842 I] went forward and was sealed to him. Brigham Young performed the sealing ... for time, and all Eternity. I did just as Joseph told me to do".
Meanwhile, in 1835 she married another man, Adam Lightner a non-Mormon. They had two children and she was pregnant with her third at the time she was sealed to Joseph Smith in 1842. “I went forward and was sealed to him. Brigham Young performed the sealing, and Heber C. Kimball the blessing." After the sealing she continued to live with her first husband Adam. That summer they moved fifteen miles away at Pontoosuc. Following the death of Joseph Smith Mary went briefly back to Nauvoo. In the fall of 1844 Brigham Young and Heber Kimball offered themselves to Smith's widows as proxy husbands and Mary accepted Young's proposal. She was sealed to him for time in a proxy marriage on May 22, 1845: "I was also sealed to B Young as proxy for Joseph," she wrote, though she continued to live with Adam.
When Brigham Young and the church left Nauvoo to emigrate to Utah, Mary and Adam stayed behind. They eventually moved to Utah 17 years later settling in the town of Minersville 217 miles from Salt Lake City, the seat of the church and Brigham Young. In her later years she would often supplicate the church for monetary assistance appealing to them on the basis of her connection with Joseph and Brigham.
Mary Elizabeth and her sister Caroline were instrumental in salvaging printed pages of the Book of Commandments when the printing press was destroyed by a mob on July 20, 1833.