Thomas Day was born September 2, 1814 in Wolverhampton, Stafford, England. He joined the Methodist Church, eventually becoming a preacher within the group, and married a young widow named Ann Andrus Danks. Day joined the Church of Jesus Christ of Latter-day Saints (LDS) on September 2, 1842 and his wife joined ten days later. He served as a traveling LDS missionary in Leamington, Oxfordshire, Northamptonshire and Leicestershire, England between 1843 and 1849. While he was serving as a missionary, Day’s wife and only child died.

Day immigrated to the United States in 1850 on the Josiah Bradlee, having been ordained by Orson Pratt to preside over the emigrating members of the Church. He remarried and settled in Springville, Iowa, until he immigrated to the Salt Lake Valley in 1852. He was present in Salt Lake City at the groundbreaking of the Salt Lake Temple on February 14, 1853. After moving to Utah he served as a missionary to the Salmon River Indian mission in Idaho.

Following the exodus southward from Salt Lake City due to the threat of the approaching U.S. Army in 1858, Day remained in Spanish Fork and assisted in preliminary efforts to lay out orchards in the area. In Spanish Fork he served as Teacher, School Trustee, member of the City Council, Ward Teacher, and Water Master. By 1863 Day had entered into the practice of polygamy and one of his two wives died in that year. He volunteered to move to the Muddy River area in Southern Utah as part of colonizing effort in that region.

Returning from this experience, he settled in St. George with his one wife and six children and found work as a sheepherder in Kanarra. He married a widow in St. George and also became one of the laborers in the newly finished St. George temple. Due to health problems, Day moved to Circle Valley, Piute County, in 1877. Day died in Circleville on January 6, 1893.