Richard Thomas Dunn was born on August 21, 1918 in Normal, IL, to Richard Francis Dunn and Clara Huxtable. After graduating from University High School in 1936, Dunn enrolled at the University of Illinois. While attending the U of I, Dunn entered into the R.O.T.C. program for undergraduates. Shortly after completing his R.O.T.C. training and graduating in 1940 with a bachelor of arts degree, he was commissioned into the U.S. Army Reserve Corps as a Second Lieutenant of Infantry.
During World War II Dunn spent most of his time as a military training officer in Springfield, IL while assigned to a brief commission in the Philippines. Dunn quickly and successfully rose through the Army ranks during the war years. In 1946, the time he was released from active duty, he had risen to the rank of lieutenant colonel. In December 1951, he was assigned to active duty for a second time during the Korean War. During his second tour of duty he served as Battalion Commander and Inspector General of the 44th Infantry Division. Dunn was released from active duty in August 1953.
Following the Korean War Dunn was assigned to various military positions, most notably as Commander of Emergency Operations Headquarters in February 1968. Dunn formally ended his military career by retiring in 1970. During his distinguished military career, Dunn was awarded with the following: American Defense Service Medal; American Theater Ribbon; Asiatic-Pacific Theater Ribbon; World War II Victory Medal; National Defense Service Medal; the Legion of Merit.