Samuel Moffett Ralston was born Dec. 1, 1857, on farm near New Cumberland, Tuscarawas County, Ohio. He was the son of John and Sarah (Scott) Ralston. In 1865(6), his parents moved to Owen County, Indiana. In 1873, they lost their farm and moved to Rontanent, Indiana to mine coal. They later returned to Owen County.

On December 26, 1881, Ralston married Mary Josephine Backous, who sadly died within a year. For seven years, Ralston taught school during the winter months and attended school during the summer months. He spent one term at Northern Indiana Normal School at Valparaiso, then transferred to Central Indiana Normal School, in Danville, Indiana. He graduated on August 1, 1884. He then studied law at the office of Robinson & Fowler in Spencer, Indiana and was admitted to the bar of the Owen County Circuit Court on January 1, 1886.

From 1886 to 1913 he practiced law in Lebanon, Indiana. He was defeated in the State Senate race in 1888. On December 30, 1889 he married Jennie Craven, the mother of his two sons, Emmet and Julian, and one daughter, Ruth. He had two more unsuccessful runs to be the Democratic nominee for Indiana Secretary of State in 1896 and 1898. However, he became the Democratic governor of Indiana from 1913 to 1917. After leaving office he resumed practicing law in Indianapolis.

Ralston returned to politics in 1922 when he was elected to the U.S. Senate. On February 13, 1924, he made his maiden speech on the Mellon Tax Plan and ordered that his name be withdrawn as a candidate for the Democratic presidential nominations. He died October 14, 1925.