Stating that his team needed to add character and leadership, Cliff Fletcher finally completed a trade for McDonald seven years after his first attempt.
McDonald was acquired by the Calgary Flames, along with a draft pick, in exchange for Bob MacMillan and Don Lever on November 25, 1981.
The deal occurred one day after the last place Rockies lost to the Flames by a 9–2 score.
Once the team's plane landed in Winnipeg, McDonald was informed of the trade and told to return to Calgary.
Angered at first, he viewed the deal as an insult, that the worst team in the NHL had rejected him.

McDonald also felt the pressure of having to replace two popular ex-Flames in MacMillan and Lever while also working to overcome a separated shoulder he suffered earlier in the year with the Rockies.
He made his debut with the Flames the following night, a 7–1 victory over the Los Angeles Kings, after which McDonald remarked that it was the most fun he had playing the game in a long time.
He was given a loud ovation by the fans who immediately embraced him as a local hero, even though it took him seven games before he scored his first goal as a member of the Flames.
He scored 34 goals in Calgary, and combined with the 6 scored in Colorado, finished with his fifth 40-goal campaign in six years.

The 1982–83 season was dominated by McDonald's battle with Wayne Gretzky of the Edmonton Oilers for the league lead in goals.
Amidst the best offensive season of his career, McDonald scored a hat trick against Pittsburgh to give him 47 goals at the mid-season break for the 1983 All-Star Game, a total that tied his career high.
He was named to the starting lineup for the All-Star Game and was the league's leading goal scorer at that point, two ahead of Gretzky.
McDonald finished with 66 goals, five short of Gretzky's 71.
At that time, only Gretzky, Mike Bossy and Phil Esposito had ever scored more goals in one NHL season.
McDonald was named to the Second All-Star Team for the second time in his career and was voted the winner of the Bill Masterton Memorial Trophy, given to the player who "best exemplifies the qualities of perseverance, sportsmanship and dedication to hockey".
His 66 goals remains a Flames' single season record.

Following the trade of Phil Russell in the summer of 1983, McDonald and Doug Risebrough were named co-captains for the 1983–84 season.
They were joined by Jim Peplinski the following season.
McDonald missed 15 games due to injuries which reduced his scoring to 33 goals and 66 points, but he played in his fourth All-Star Game.
He scored the first Flames goal in the Olympic Saddledome, on the building's opening night of October 15, 1983.

McDonald became the 21st player in NHL history to score 400 career goals, reaching the mark in a 7–4 loss in Los Angeles on December 21, 1983.
He was initially credited with scoring the milestone goal in his previous game, against the Winnipeg Jets, but after reviewing a replay of the goal himself, McDonald asked the league to credit it to teammate Eddy Beers who had deflected his shot.
His injury problems worsened in 1984–85 as he missed the start of the season with pulled muscles and was limited to just 43 games.

As the 1985–86 season approached, McDonald endured questions about whether he was reaching the point where age and injuries meant he could no longer be an effective NHL player.
Hoping to prove himself, he set a goal of playing all 80 games for the Flames.
He succeeded, and scored 28 goals and 71 points in the process, despite dislocating his thumb in the pre-season and suffering minor knee and hip injuries during the course of the year.
He later said it was a matter of pride to him not to miss a game.
In the playoffs, McDonald was witness to one of the most infamous mistakes in NHL history.
With the score tied at two in the seventh game of the Smythe Division final against Edmonton, McDonald chased Oilers' rookie Steve Smith around the Edmonton net.
Smith attempted to pass the puck forward, but inadvertently hit the back of goaltender Grant Fuhr's skate, deflecting the puck into his own net.
Stating that his team needed to add character and leadership, Cliff Fletcher finally completed a trade for McDonald seven years after his first attempt. McDonald was acquired by the Calgary Flames, along with a draft pick, in exchange for Bob MacMillan and Don Lever on November 25, 1981. The deal occurred one day after the last place Rockies lost to the Flames by a 9–2 score. Once the team's plane landed in Winnipeg, McDonald was informed of the trade and told to return to Calgary. Angered at first, he viewed the deal as an insult, that the worst team in the NHL had rejected him.
McDonald also felt the pressure of having to replace two popular ex-Flames in MacMillan and Lever while also working to overcome a separated shoulder he suffered earlier in the year with the Rockies. He made his debut with the Flames the following night, a 7–1 victory over the Los Angeles Kings, after which McDonald remarked that it was the most fun he had playing the game in a long time. He was given a loud ovation by the fans who immediately embraced him as a local hero, even though it took him seven games before he scored his first goal as a member of the Flames. He scored 34 goals in Calgary, and combined with the 6 scored in Colorado, finished with his fifth 40-goal campaign in six years.
The 1982–83 season was dominated by McDonald's battle with Wayne Gretzky of the Edmonton Oilers for the league lead in goals. Amidst the best offensive season of his career, McDonald scored a hat trick against Pittsburgh to give him 47 goals at the mid-season break for the 1983 All-Star Game, a total that tied his career high. He was named to the starting lineup for the All-Star Game and was the league's leading goal scorer at that point, two ahead of Gretzky. McDonald finished with 66 goals, five short of Gretzky's 71. At that time, only Gretzky, Mike Bossy and Phil Esposito had ever scored more goals in one NHL season. McDonald was named to the Second All-Star Team for the second time in his career and was voted the winner of the Bill Masterton Memorial Trophy, given to the player who "best exemplifies the qualities of perseverance, sportsmanship and dedication to hockey". His 66 goals remains a Flames' single season record.
Following the trade of Phil Russell in the summer of 1983, McDonald and Doug Risebrough were named co-captains for the 1983–84 season. They were joined by Jim Peplinski the following season. McDonald missed 15 games due to injuries which reduced his scoring to 33 goals and 66 points, but he played in his fourth All-Star Game. He scored the first Flames goal in the Olympic Saddledome, on the building's opening night of October 15, 1983.
McDonald became the 21st player in NHL history to score 400 career goals, reaching the mark in a 7–4 loss in Los Angeles on December 21, 1983. He was initially credited with scoring the milestone goal in his previous game, against the Winnipeg Jets, but after reviewing a replay of the goal himself, McDonald asked the league to credit it to teammate Eddy Beers who had deflected his shot. His injury problems worsened in 1984–85 as he missed the start of the season with pulled muscles and was limited to just 43 games.
As the 1985–86 season approached, McDonald endured questions about whether he was reaching the point where age and injuries meant he could no longer be an effective NHL player. Hoping to prove himself, he set a goal of playing all 80 games for the Flames. He succeeded, and scored 28 goals and 71 points in the process, despite dislocating his thumb in the pre-season and suffering minor knee and hip injuries during the course of the year. He later said it was a matter of pride to him not to miss a game. In the playoffs, McDonald was witness to one of the most infamous mistakes in NHL history. With the score tied at two in the seventh game of the Smythe Division final against Edmonton, McDonald chased Oilers' rookie Steve Smith around the Edmonton net. Smith attempted to pass the puck forward, but inadvertently hit the back of goaltender Grant Fuhr's skate, deflecting the puck into his own net.
Lanny McDonald