Born in Minneapolis, Minnesota, Hamel moved with his parents to Grafton, North Dakota.
He graduated from the University of North Dakota, then traveled in 1906 to Washington, D.C., as the private secretary to Senator Henry C. Hansbrough.
After Hansbrough's term expired in 1909, Hamel worked for the United States Department of the Interior from April 1909 to October 1915.
In February 1922, he entered the office of the Solicitor, United States Bureau of Internal Revenue.
[3] In March 1927, Hamel was hired to head the simplification division of the Joint Committee on Internal Revenue Taxation, which he left in 1929 to establish a law firm that would eventually become part of Foley & Lardner.