Royal Thompson was Caucasian. He is the son of John Thompson Jr and Georgiana Bignell.
His mother Georgina was born on March 3, 1907 in Arkansaw, Pepin County, Wisconsin, United States of America and grew up in Waterville, Pepin, Wisconsin. She married John on May 12, 1925 in Wabasha, Minnesota, USA and later passed away on January 24, 1963 in Red Wing, Goodhue, Minnesota, USA.
His father John was born on April 30, 1902 in Arkansaw, Pepin, Wisconsin and grew up in Eau Galle, Dunn, Wisconsin, USA. After marrying Georgina in 1925, he worked as a farmer in Spring Brook, Dunn, Wisconsin, USA. John passed away on February 14, 1973 in Red Wing, Goodhue, Minnesota, USA.