Roy Riales was born December 24, 1909 in Mena, Polk County, Arkansas. He was educated at Georgia-Carolina School of Commerce in Bronswick, Georgia and after completing courses in Business Administration he received a diploma in 1925. Before Riales went into politics, he was a civil engineer by profession. He began his profession as a civilian staff member of the army corps of engineers. He also was with the general land office, re-surveying boundaries for the forest service, other government departments, biological survey in several state and with the United States Resettlement Administration. In 1938, Riales' conservation interest led him to run for the state legislature from Polk County, which at the time had one representative. Riales was elected to five consecutive two year terms to the Arkansas House of Representatives (1938-1948) and served as speaker of the House in the 1947-1948 session. It was at this time that Riales also had the opportunity to act as Governor of Arkansas for three days while the lure of football on New Year's Day, 1948, led Governor Ben Laney, to Birmingham, Alabama, to witness Arkansas beat William and Mary College, and Lieutenant Governor Nathan Gordon to the Cotton Bowl in Dallas, Texas.

That was not Riales' only venture into politics. He served as secretary to U.S. Congressman Fadjo Cravens, of Fort Smith, from 1939-1944, while at the same time serving as a state representative in the Arkansas Legislature. Riales resigned his secretary position to join the United States Army, but was injured in a bus wreak April 18, 1944, on the way to Camp Robinson in North Little Rock, where he was to be inducted into service. As a result he became active with the Arkansas National Guard advancing from the rank of lieutenant to lieutenant colonel. Furthermore, Riales was Provost Marshall, and Inspector General during World War II, and served three years as Liaison Officer in Washington, D.C. for the Arkansas National Guard.

In 1940, Riales became affiliated with Grapette, a soft drink manufacturing company located in Camden, Ouachita County, Arkansas. Riales moved to California, in 1947, to work in the newly opened Grapette distribution plant in Tulare. While in California, Riales served in a number of public jobs, including a postmaster from 1951, until his resignation in 1952 to return to the political arena in Mena, Arkansas.

Riales campaigned throughout his district and was elected to the state senate. Riales served as state senator for the sixth district, representing Polk, Howard, Sevier, and Little River counties, from 1955-1961. During that time he was unanimously elected President Pro Tempore of the Arkansas State Senate in the 1959-1960 session. Throughout his extensive career as a public servant Riales served on several legislative committees, including: Insurance, Workman's Compensation, Budget and Public Expenditures, Refunding, Claims, Finance and Banking, in addition to serving as Chairman of the Federal Relations, Interstate Cooperation , Veterans Affairs, and Roads and Highways committees.

He was married to Madean Wood of Mena and had two children Roy Lee Riales Jr., and Thomas Dean Riales. He continued to be a life-long Democrat until his death in November 1, 1985.