Floyd E. Thompson was born in Roodhouse, Illinois, December 25, 1887, the son of Alonzo and Sarah (Edwards) Thompson. He is descended from Colonial stock. His earliest known paternal ancestor was John Thompson of Virginia, a soldier in the Revolutionary War. All his ancestors were farmers and he followed that occupation until his graduation from high school. After leaving the public schools he taught school for three years and also prepared himself for the bar by private study. He was admitted to practice in Tennessee and Illinois in 1911. He located in East Moline, where he practiced law and edited and published the East Moline Herald until his election as State’s Attorney of Rock Island County in November 1912. In December 1915, he was elected president of the Illinois State’s Attorney’s Association. He was re-elected State’s Attorney in 1916 and served in that office until April 1919, when he was elected a member of the Supreme Court to fill a vacancy. He was re-elected for the full term beginning in June 1921. From 1921 to 1923 he was chairman of the Section of Criminal Law of the American Bar Association, and he has been vice-president of the American Institute of Criminal Law and Criminology. He was a charter member of the American Law Institute and was active in its work. He was also a member of the Illinois State and Rock Island County Bar Associations, the Rock Island Chamber of Commerce, the Moline After Dinner Club, the Black Hawk Hills and the Short Hills county clubs, the Sons of the American Revolution, the Sons of Union Veterans, and was an Elk, an Odd Fellow, a Knight of Pythias, a Moose, an Eagle, a Modern Woodman, and a Mystic Worker.