Clarence was the son of Tom and Semilia Thompson, who came to Ypsilanti Township in 1905, settling on a farm one mile east and a half mile south of Ypsilanti, Stutsman County, North Dakota. Clarence accompanied his parents to the Ypsilanti community.
In 1916, Clarence was married to Irene Haeney, who was a teacher in the Ypsilanti community, and they ran his mother's farm in Winfield Township.
They left the farm in 1937, and moved to Minnesota. They had two children, Francis and Gerald, who received their grade school education in Winfield Township, both attending high school in Ypsilanti.