Yes, Joseph Smith, the founder and first prophet of the Church of Jesus Christ of Latter-day Saints, practiced plural marriage, a principle which he taught among the early members of the Church. The practice of polygamy, or plural marriage, was introduced as a religious principle beginning in the early 1840s, though its full scope and official documentation came more into light after Smith's death. The revelation on plural marriage is recorded in Doctrine and Covenants section 132, wherein it is stated that Joseph Smith received divine instruction from God to practice and teach this principle
Documentary and material evidence confirms that Joseph Smith practiced plural marriage, entering into approximately 30 to 40 conjugal unions between the mid-1830s and his death in 1844. The most authoritative documentation derives from the 1892 Temple Lot case depositions, where numerous women testified under oath to having been married to Smith, including Emily Partridge, Malissa Lott, and Lucy Walker (Compton, *In Sacred Loneliness*, 1997; Transcript, *The Temple Lot Case*, 1892). Contemporary manuscript evidence includes the July 12, 1843, revelation now canonized as Doctrine and Covenants