Dick Thornton was a star defensive back and wide receiver for the Winnipeg Blue Bombers from 1961 to 1966. Thornton also subbed for Kenny Ploen when Winnipeg's starting quarterback was injured. He won two Grey Cup games with them, the first in 1961, the 49th Grey Cup that went in overtime, the second in 1962, the 50th Grey Cup, played in horrendous fog, both against the Hamilton Tiger-Cats. In 1961, he did not play in the title game due to an injury. However, he was an important cog as cornerback on the 1962 team, after intercepting 4 passes and returning one for a touchdown, recovering two fumbles, and blocking a kick during the regular season.
In 1963, Thornton intercepted 6 passes, 3 of them for touchdowns, also returning a fumble for a touchdown. In 1964, he missed most of the season due to an injury, but recovered well in 1965, when he starred again at defensive back and wide receiver, his team making it to the 53rd Grey Cup, the nearly supernatural "Wind Bowl", this time losing to Hamilton. After 1966, when the Bombers did not make the playoffs, change was imminent.
Thornton was traded to the Toronto Argonauts in 1967 and played with them up to 1972 as one of the best defensive backs in that era. Notably, he intercepted 7 passes in 1969 from the cornerback position. He was a CFL all-star and played in the rainy 59th Grey Cup game in 1971. Despite his return of an interception of 54 yards, Toronto lost a defensive struggle to the Calgary Stampeders 14 to 11.