Marlin Edmonson was born in Illinois to James and Nora Edmonson. He had six siblings. The family moved outside of Topeka and then to Herrington in 1926. He graduated from Herrington High in 1931. For several years he worked at Wilks and Hunt Hardware but began his career as a railroad brakeman with the Rock Island line on June 16, 1941. He was a brakeman for the Rock Island line for over 36 years, except during the war. From November 1942 through January 1946, he served in the Military Railway Service with the 5th Army in Europe. As a Sargent, he acted as a conductor in Belgium, France, Luxemburg and Germany. He recalls of his service that, "there were no hours of service. You went until you got there, whether it took one day or a week." Edmonson married Margaret Criss and they had two daughters and two grandchildren. He was a member of the First Baptist Church and the Kansas Lodge 307 AF & AM Masonic Lodge in Herrington, Kansas.