Daniel Mulford Valentine was born June 18, 1830 at Kirkwood (Shelby County), Ohio to John Winans and Rebecca (Kinkennon) Valentine. In 1854, Valentine moved to Adair County, Iowa, where he completed his law studies, served as county surveyor, and taught school for a year. On June 26, 1855, he married Martha Root.
Valentine was admitted to the bar in 1858, and served that year as attorney of Adair County before moving to Leavenworth, Kansas, and then to Franklin County, Kansas. He was elected as representative to the Kansas Legislature in 1861 and to the Kansas Senate in 1862. In 1864, he was elected judge of the Fourth Judicial District, and in 1868 was elected an associate justice of the Supreme Court of Kansas. He was re-elected three times, for a term of office which extended to 1893. Valentine died on August 5, 1907 at Topeka (Shawnee County), Kansas. The Valentines' four daughters and five sons included sons Delbert A. Valentine and Louis F. Valentine, who became newspaper editors in Clay Center, Kansas.
From the guide to the Daniel Mulford Valentine papers, 1844-1924, (University of Kansas Kenneth Spencer Research Library Kansas Collection)