Arthur W. Hart was born October 16, 1869 in Bloomington, Bear Lake County, Idaho the son of James H. and Sabina "Scheib" Hart. Arthur's father was a prominent lawyer and politician. Arthur received his basic education at the Fielding Academy in Paris, Idaho and the Brigham Young College (BYC) in Logan, Utah. After finishing his studies at the BYC he enrolled in the University of Deseret (now University of Utah) during the 1880s. At the University of Deseret he studied law and graduated in 1890. After Arthur's graduation he continued to study law under his brother, Judge Charles H. Hart, who had a law office in Logan, Utah.

In 1896 Arthur was called by his church, the Church of Jesus Christ of Latter-day Saints, to serve as a missionary in Germany. Hart proselyted for two and a half years and served as president of the Stuttgart Conference. In addition to his time in Germany he also traveled to Switzerland, France, and England.

Arthur returned to Utah in 1898 and continued to pursue a career in law. Later that year he was admitted into a law firm in Preston, Idaho where he continued to work for the next forty-six years. In 1901 Arthur was elected County Attorney of Oneida County on the Democratic ticket. Arthur served as mayor of Preston and was active in local civic affairs. He was also instrumental in organizing the Oneida Irrigation Company and served as its secretary for many years.

On August 22, 1900 Arthur married Ada D. Lowe in Salt Lake City and they later had eleven children together. On August 21, 1903 he took a second wife when married Evadyna Henderson in Preston, Idaho. They later had thirteen children together. (Although the Church of Jesus Christ of Latter-day Saints had publicly stated that it would no longer practice polygamy after 1890, it was often practiced in secret until 1903 when the Church officially stated that it would no longer allow plural marriages.)

Arthur retired in 1947 and moved to Salt Lake City, Utah. He died on April 7, 1949 in Salt Lake City.