The 33-year-old informed his teammates and coaches of his decision, and spoke glowingly of the club he spent his entire AFL career at.
"I am incredibly grateful for the opportunity to have represented the Club, and have always worn our jumper with pride," Mackay said.
"To all my teammates, coaches and the staff of this great club, thank you. I am privileged to have met and worked with so many amazing people.
"To the Members and supporters, thank you for your passionate and unrivalled support, and playing in front of you has been an absolute thrill and honour.
"To my family, thank you is not enough.
"I will be eternally grateful for the sacrifices you have made in allowing me to chase my dream and I can’t wait to embark on the next chapter."
The 247-gamer was drafted by the Crows with Pick 48 in the 2006 National Draft, and averaged 17 disposals, three marks and three tackles over the course of his 14-year service at West Lakes.
"D-Mac's playing career speaks for itself – 248 games in 15 seasons – he has been durable and super-reliable for this Club for a long time," Nicks said.
"It is a credit to him the way he has continually reinvented himself and improved his game, and this season he has played some of the best football of his career.
"His reputation off the field and everything that he brings to other areas of the Club is equal to what he has achieved as a player.
"He is the ultimate professional when it comes to his training and preparation, he is a selfless teammate who shows care for others and is an outstanding role model for young players.
"We wish him and his wife Sarah, and their three children William, Lucy and Tom, all the best in the next phase of their lives and he leaves with our utmost respect and thanks for his contribution."
Mackay will finish his career having played the ninth most games in the Crows' history.