[3] After attending public school, the boy was sent to the Poland Seminary, where he became great friends with the young William McKinley, also a student there.
[3] He was admitted to the Illinois Bar in 1873, and practiced law in Danville until 1898, gaining fame for his brilliance and eloquence as a criminal defense attorney.
[4] In 1897, Calhoun's friend, William McKinley, who had recently been sworn in as President, appointed him as special counsel to US Consul General in Cuba Fitzhugh Lee, to investigate the death of Dr. Ricardo Ruiz, a dentist and naturalized American citizen who died in a Cuban jail after his arrest for sabotage.
[3] On March 9, 1898, McKinley appointed Calhoun as a commissioner of the Interstate Commerce Commission for a six-year term.
[3] In 1909, President William Howard Taft appointed Calhoun as Envoy Extraordinary and Minister Plenipotentiary to China.