John Whitmer was born on August 27, 1802, in York, Pennsylvania to Peter Whitmer, Sr. and Mary Musselman. By the 1820s, the Whitmer family had moved to a farm in Fayette, in New York's Finger Lakes area. John Whitmer's brother, David, and his entire family became members of the Mormon Church.
Whitmer was baptized into the Church by Oliver Cowdery in June of 1829, nearly a year prior to the formal organization of the Church of Christ, the original name of The Church of Jesus Christ of Latter-day Saints. In that same month, Whitmer became one of eight men who signed a testimony that they had handled and been shown the Golden Plates, which was the ancient text translated into the Book of Mormon. Known as the "Testimony of the Eight Witnesses" the statement was printed in the first edition of the Book of Mormon and has been included in almost every subsequent edition.
The original Church was formally organized on April 6, 1830, in the Whitmer home in Fayette. Whitmer was one of the earliest members, and he was ordained an elder of the church on June 9, 1830. The next year, on March 8, 1831, Joseph Smith received a revelation from God, calling Whitmer to "write and keep a regular history" of the Church. This revelation was printed in the Book of Commandments (precursor to the Doctrine and Covenants) as section 50, and in the Doctrine and Covenants originally as section 63. The revelation is now section 47 of the current LDS edition.
John Whitmer was active as a servant to the Church in Missouri. He left for Jackson County in 1831 and took refuge in Clay County in 1833. He petitioned the Missouri government for redress on behalf of the beleaguered Saints. He purchased land for the Church in Caldwell county and founded the settlement at Far West as a safe haven for the members of the Church.
After the failure of the Kirtland Safety Society leaders of the Church left Kirtland for Missouri. Dissension arose in Far West, and the Whitmers participated in it against the Prophet Joseph Smith, resulting in John Whitmer's excommunication. The Whitmer family moved to Richmond in neighboring Ray County. Eventually, John Whitmer brought his family back to Far West. The family remained there, even as most of the Saints escaped to Illinois. He purchased property and established a large farm. After the martyrdom of Joseph Smith, David Whitmer founded a new, but short-lived Church, the Church of Christ (Whitmerite), of which John became a member for a time. John Whitmer died on July 11, 1878, in Far West. His history, The Book of John Whitmer, Kept by Commandment is in the archives of the Community of Christ, formerly known as the Reorganized Church of Jesus Christ of Latter-day Saints.