Chouinard was selected by the Atlanta Flames with the 28th overall pick in the 1974 NHL Entry Draft, following a successful junior career with the Quebec Remparts in which he was a regular at the age of 15. He was one of the first underage players available in the entry draft after the National Hockey League's decision allowing the drafting of underage players. While playing with Atlanta, he set records for scoring goals in six consecutive games from November 14 to November 24, 1978; he was the first Flame to score 50 goals in a season in the 1978–79 season. Chouinard scored the final goal in Atlanta Flames history during the 1979-80 NHL playoffs in a 5-2 home team loss against the New York Rangers. He remained with the team when it relocated to Calgary for the 1980–81 season. He left the Flames franchise as its all-time leader in points (529) and assists (336) (records since broken) on September 6, 1983, when he was traded to the St. Louis Blues for future considerations.