Lawrence R. Flake, Prophets and Apostles of the Last Dispensation (Provo, UT: Religious Studies Center, Brigham Young University, 2001), 355–57.
Born: 18 January 1806, Smith County, Tennessee
Quorum of the Twelve Apostles: 15 February 1835 (age 29)
Excommunicated: 11 May 1838
Died: 24 April 1883 (age 77), Independence, Missouri
In the fall of 1831 William McLellin, who had been baptized by Hyrum Smith, traveled to Orange, Ohio, where an important conference was being held. There he became acquainted with the Prophet Joseph Smith. At William’s request, the Prophet inquired of the Lord concerning him and received a revelation in which Brother McLellin was both commended and reproved (D&C 66). A few days later at a special conference in Hiram, Ohio, concerning the publication of the Book of Commandments, the Lord gave by revelation his preface to that book (D&C 1). Brother McLellin, who had received a better-than- average formal education and had taught school in five states, criticized the language of the revelation as being inferior. The Lord then sent another revelation in which He challenged “him that is the most wise among you” to imitate “even the least that is among [the revelations]” received by Joseph Smith (D&C 67:6). The Prophet recorded, “William E. M’Lellin, as the wisest man, in his own estimation, having more learning than sense, endeavored to write a commandment like unto one of the least of the Lord’s, but failed The Elders and all present that witnessed this vain attempt of a man to imitate the language of Jesus Christ, renewed their faith in the . . . revelations which the Lord had given to the Church through my instrumentality.” 
Brother McLellin repented and filled a mission with Parley P. Pratt, but on 8 March 1833, in another revelation, the Lord declared, “I am not well pleased with my servant William E. McLellin” (D&C 90:35). Again McLellin sought to turn from his weaknesses and gain the approval of the Lord. That winter he served as an assistant teacher in the School of the Elders in Kirtland. When the Quorum of the Twelve was organized in February 1835, William E. McLellin was chosen to be an apostle. Soon after this call, while on a mission to the East, Elder McLellin wrote a letter rebuking the presidency of the Church. As a result, the fellowship of the quorum was withdrawn until he humbled himself again and asked forgiveness a few weeks later. In the spring of 1838, during the Missouri persecutions, William completely rejected his fellow leaders of the Church and returned to his life of sin.
Following his excommunication, filled with the spirit of bitterness, McLellin joined the mobs that afflicted the Saints. While the Prophet was in a Missouri prison, McLellin and others looted his home and stable. Later the large and physically strong McLellin asked the sheriff holding Joseph Smith in prison for the privilege of flogging the Prophet. The sheriff agreed—if Joseph Smith would fight. Joseph said he would fight if he did not have to wear leg irons. McLellin was not willing under those conditions unless he could use a club and the Prophet be weaponless. Even to this Joseph agreed, but the jailor would not allow such an unfair fight. At one point, following the problems in Far West, McLellin attempted unsuccessfully to establish his own church. He retained his convictions that the roots of Mormonism were authentic and involved himself almost constantly with various splinter groups including the Hedrikites (or Church of Christ Temple Lot) in Independence, Missouri. Near the end of his life he was admonished, in a correspondence with Joseph F. Smith, who visited him in 1878, to “return to the fold,” an invitation which he never accepted.  On 14 March 1883, he died in Independence where he had been living for the last fifteen years of his life.
 History of the Church, 1:226.
 Jan Shipps and John W. Welch, eds., The Journals of William E. McLellin: 1831–1836 (Provo, UT: BYU Studies, 1994), 355. See also Calvin N. Smith, “McLellin Became Enemy of Church,” Church News, 27 October 1985, 13; “Excerpts from Journal and Writings of William E. McLellin, Early Apostle,” Church News, 24 October 1992, 13.