Born in Grayson County, Kentucky, on 22 May 1811, Shields moved to land in the Black Hawk Purchase shortly after the treaty was signed.
From 1835, he ran a store in the lead mines at what became Dubuque, Iowa, and sold goods throughout the lumber-producing regions of Wisconsin and Minnesota.
He served several terms as alderman in Dubuque and was elected later mayor of the city.
He won reelection in the multi-member District 24, serving alongside Warner Lewis, Maturin L. Fisher, and William W. Hamilton.
Shields died on 25 June 1856, while visiting St. Anthony, Minnesota, for health purposes.