Thomas was adopted as a baby but his adoptive mother died when he was five. His father remarried three times and Thomas had an unsettled childhood.
He did not learn he was adopted until he was 13, from his grandmother.
From the age of 12 he worked in the restaurant business. He was a high-school dropout and left home after the 10th grade. He founded the Wendy's franchise restaurant chain in 1969.
He was on the boards of directors of the Children's Hospital in Columbus, Ohio and the St. Jude Research Hospital in Memphis, Tennessee, and won the Horatio Alger Award in 1979.
In 1992 he established the Dave Thomas Foundation for Adoption, to promote adoption law simplification and reduce the costs of adopting in the USA.
He traced his birth parents but they had already died when he located them.
He had a quadruple heart by-pass operation in 1996 and his kidneys failed in 2001.
Dever, Maria, and Dever, Aileen. Relative Origins: Famous Foster and Adopted People. (Portland: National Book Company, 1992) Who's Who in America, 1996 Thomas, R. David. Dave's Way: A New Approach to Old-Fashioned Success. (New York: G.P. Putnam's Sons, 1991) "Dave Thomas Foundation for Adoption." [Includes portrait]. Available at:  Den. "Entrepreneur's History: Dave Thomas (Wendys)." Available at:  Dottie, Enrico. "Roots of Ambition: Famous Businessmen Who Were Adopted." Available at: . Originally published in USA Today, 5 September 1997 "Wendy's Founder Dave Thomas Dies." Associated Press wire story, 8 January 2002, 9:13 AM.