Born in the town of Arlington, Columbia County, Wisconsin, Caldwell was a farmer in Lodi, Wisconsin. He was also president of the Columbia Bank of Lodi and of Lodi Union Agricultural Society. Caldwell served on the Lodi Board of Education, the Columbia County Board of Supervisors, and was the president of the village of Lodi.
He served on the local draft board during World War I and World World War World War II Caldwell was active in the Republican and was a presidential elector in the United States presidential election of 1928.
In 1915, 1921, 1923, and 1925, Caldwell served in the Wisconsin State Assembly. He then served in the Wisconsin State Senate from 1927 to 1931.
Caldwell died in a hospital in Madison, Wisconsin after an illness of few months.