John Nelson Calhoun was born in Birmingham, Iowa, on December 2, 1903. He received his B. A. in English from Parsons College of Fairfield, Iowa, in 1926. Three years later he completed his law degree at the University of Iowa and was admitted to the bar. That same year, he established a law practice in Keosauqua, Iowa.
An active Republican, Calhoun served as a senator in the Iowa state legislature from 1933 to 1937. In 1936, he mounted an unsuccessful campaign for Congress. Upon leaving the legislature, Calhoun moved to Burlington where he began a new law firm while continuing his affiliation in Keosauqua.
John Calhoun was a member of the National Guard. During World War II, he was released for active service in the army. Stationed in the Middle East as part of the Judge Advocate General's Office for most of the war, he held the rank of lieutenant colonel when discharged in 1946.
Following his tour of duty, Calhoun returned to Burlington and his legal practice. In 1948, he again mounted a campaign for the Senate; however, he failed to secure his party's nomination. Active in both professional and civic affairs, Calhoun belonged to the Rotary, American Legion, and various other service organizations. John N. Calhoun died in 1972.