Born in Williamsburg, Iowa, Morrin began working when he was 12 years old.
He joined the International Association of Bridge and Structural Iron Workers, and in 1909 was elected as president of his local union, becoming a business agent in 1910.
[1][2] Morrin became general organizer of the international union in 1917, and was elected as president in 1918.
[3] He was also active in the St. Louis Trades Council Union, editing its newspaper from 1917 until 1941.
[1] He retired as president at the start of 1949, and was granted a salary of $25,000 a year and use of a personal automobile, in exchange for providing advice on request.