Growing up in Quebec City, Guy Chouinard was known for his ability to score goals. All through his days of minor hockey, he scored seemingly at will, as many of the natural goal scorers do. So good was Chouinard that he was a regular with the QMJHL's Quebec Remparts at the age of 15. In that rookie year, he was a major contributor, scoring 29 goals and 70 points. The next year, still an underager at 16, he netted 43 goals and 129 points. At 17, he scored 75 goals and 85 assists for 160 points in just 62 games and was selected in the second round of the 1974 NHL Amateur Draft by the Atlanta Flames, 28th overall.
At the age of 18, with two years of junior eligibility left, Chouinard played his first five games in the NHL with the Flames but was held off the scoresheet. Rather than return to the Remparts, Chouinard was sent to the Omaha Knights of the CHL where it was felt he would face stiffer competition which would aid in the development of his skills. In 70 games, he scored 28 goals and 68 points.
Chouinard finally got his chance to play in the NHL on a full-time basis in 1976-77, playing 80 games and scoring 17 goals and 50 points. He improved to 28 goals and 58 points the next year but it was the 1978-79 season when he had the year of his life, scoring 50 goals and 57 assists for 107 points. That excellent year was followed by a pair of 31-goal seasons, the second of which came in Calgary, after the club had re-located there for the 1980-81 season.
Chouinard remained with the Flames through the 1982-83 season, but despite being only 26, his best years were already behind him. In 80 games that year, he did scored 72 points but just 13 goals. He finished his NHL career a year later, playing with the St. Louis Blues. After returning for the first nine games of the 1984-85 season in the IHL with Peoria, Chouinard opted to hang up the skates, his heart no longer in the competitive game.