He made the first interception ever in the American Football League, in the first AFL game against the Boston Patriots. He had seven interceptions in his first three games, and his 11 pickoffs in 1960 are still a Denver club record. He shares the team record for interceptions in a game with four, a feat he accomplished 18 September 1960 at Buffalo.
Gonsoulin was a Sporting News AFL All-League player in 1960, 1962, and 1963, and an AFL Western Division All-Star in 1961, 1964 and 1966. His amazing durability and toughness enabled him to start 61 consecutive games at one point in his career. He was also the captain of his college team at Baylor. "Goose" Gonsoulin was selected to the second unit of the American Football League All-Time Team.