Cadwell was born May 22, 1836, in Nanticoke Springs, New York.
After spending his youth in New York and Wisconsin, Cadwell served as a conductor for the Mobile and Ohio Railroad. In 1860 he married Anna Johnson and continued his railroad career. In 1862, he enlisted in the 2nd New York Cavalry.
Following the Civil War he returned to the Midwest and ran trains for the Chicago, Milwaukee, & St. Paul Railroad in Iowa and the Dakotas. In 1883 he moved to Dennison, Iowa, and began a career in banking. He remained active is the community and its civic organizations.
He died July 8, 1925, and is buried in Phelps Cemetery, Decorah Iowa.