Arnold Rüütel was born on 10 May 1928 in Saaremaa, the larger of the two islands that lie off the west coast of Estonia in the Baltic Sea. Rüütel attended the Agricultural Technical High School there, and worked as a divisional manager in the department of agriculture in Saaremaa. In 1957, at age 29, Rüütel became the head expert in livestock management, rising to the post of general director of the Estonian Institute for Animal Husbandry and Veterinary Science's experimental station a few year later. In 1963, he assumed the post of Director of the Tartu Model State Farm in eastern Estonia (near Chudskoy Ozero), managing to graduate from the faculty of agricultural sciences of the Estonian Agricultural Academy in 1964; he subsequently became rector of the Academy in 1969.
Throughout his political career, Rüütel continued his scientific research, and in 1991 earned a doctorate in agriculture. (He has also been awarded an honorary doctorate by Bentley College in the United States.) Author of over one hundred scientific papers, he has published his work in Estonia and abroad.
Rüütel's wife Ingrid is known internationally as an expert in folklore; she holds a doctorate in humanities. The couple has two daughters and five grandchildren.