Joseph Fielding Smith was born the son of Joseph F. Smith, then a member of the Quorum of the Twelve, and Julina Lambson. His mother was a midwife. As a boy he often helped his mother by driving her carriage to the various deliveries that she attended in Salt Lake City. Growing up, Smith lived with his family in the immediate vicinity of the current West High School .

Smith married his first wife, Louie Emily "Emyla" Shurtliff (born 16 June 1876) on April 26, 1898. In March 1899, Smith was called on a mission to Great Britain by Lorenzo Snow, the President of the Church. On May 12, 1899, Smith was set apart as a missionary and ordained a Seventy by his father. A small group of missionaries, including Smith and his older brother Joseph Richards Smith, left the next day for England. After his return from the British mission in July 1901, Smith and his wife Louise had two daughters, Josephine and Julina. Louise Shirtliff Smith died of complications of a third pregnancy on March 28, 1908.

Smith's married Ethel Georgina Reynolds (born 23 October 1889), the daughter of prominent LDS Church leader George Reynolds, in November 1908. They had four girls (Emily, Naomi, Lois, Amelia) and two boys, Joseph Fielding (most often called Joseph Fielding Smith, Jr.), Lewis Warren, George Reynolds, Douglas Allan and Milton Edmund. Their youngest daughter Amelia married Bruce R. McConkie; McConkie became a member of the Quorum of the Twelve Apostles shortly after Smith's death. Ethel Reynolds Smith died of a cerebral hemorrhage on 26 August 1937, at age 47.

Ethel had specifically requested that Jessie Ella Evans sing at her funeral. Evans was a member of the Mormon Tabernacle Choir and the Salt Lake County Recorder. In November Jessie and Joseph got engaged.

In April 1938, Smith married Jessie Ella Evans (born 29 December 1902) in the Salt Lake Temple. The marriage was performed by Heber J. Grant. The couple had no children, although Milton was only eleven when Joseph and Jessie married and George and Douglas were still under the age of 18. Smith's third wife died on 2 August 1971.

After completing his mission in 1901, Smith began working in the office of the Church Historian and Recorder. He authored the book entitled The Origins of the Reorganized Church and the Question of Succession in 1909, which was written to defend the LDS Church against the recent proselytizing of missionaries for the Reorganized Church of Jesus Christ of Latter Day Saints (RLDS Church) in Utah. He was the acting recorder of the general conference in 1910 when he was called as an apostle. Prior to his call as a general authority Smith served as the secretary and treasurer of the Utah Genealogical Society. In 1921 Smith assumed the office of Church Historian and Recorder which he held until 1970.

Early in his apostleship, his creationist views on the dispute between Mormonism's Biblical teachings and the Theory of evolution brought him attention. (See Mormonism and evolution).

Smith spent most of his time as an apostle living in Salt Lake City. He also was president of the Salt Lake Temple from 1945 to 1949. During this time, Smith was sent on a tour of the Spanish-American Mission of the church. Before his return to Salt Lake he informed the president of the Arizona Temple that he would recommend to the First Presidency that the temple ceremonies be translated into Spanish.

Smith served as president of the Genealogical Society of Utah and its successor the Genealogical Society of The Church of Jesus Christ of Latter-day Saints from 1934 to 1961. At the time of his release from this position he had already been president of the Quorum of the Twelve for over a decade. During the late 1950s, Smith attempted to reduce staff turnover at the Society by trying to convince the First Presidency that women should be permitted to stay on as employees after they married. However, Smith was only able to get a change to allow them to work six months past marriage.

Service abroad

Smith did, however, at times take church assignments abroad. In 1939 he was touring the missions in Europe and supervised the withdrawal of missionaries immediately prior to the outbreak of World War II. In 1950 Smith toured the Mexican Mission of the church. In 1955 Smith made an extensive tour of Asia. On this journey he dedicated Korea and the Philippines for the preaching of the gospel. In 1957 he went to Europe for the dedication of the London Temple and also presided over the excommunication of several missionaries in the French mission who had apostatized.

Smith became President of the Church on January 23, 1970, following the death of President David O. McKay. Although he only served as president of the church for two and a half years, his administration introduced several new initiatives: Area Conferences were introduced; some significant organizational restructuring in the Church Sunday School system and the Church Department of Social Services; and the church magazines were realigned into the Ensign, New Era and Friend in English, with centralized planning for all publications. His tenure was also marked by steady growth in the number of serving missionaries and the dedication of LDS temples in Ogden and Provo, Utah.