The Scot was relieved of his duties on Friday following a turbulent festive period which saw him allegedly given an uncompromising ultimatum by owner Vincent Tan to resign or be sacked.
The latter of those came to fruition, but Mackay insists he is already able to reflect on the good times he spent in the Welsh capital, which included promotion to the Premier League for the 2013-14 season.
"It is with the deepest and most sincere regret that I today confirm my sacking as manager of Cardiff City," read a statement.
"As disappointing as today's decision is, I am already able to look back at my time at Cardiff City with immense pride and joy given the number of milestones the club achieved during the last two and a half years.
"A League Cup final appearance followed by promotion to the Premiership for the very first time, achieved as winners of the Championship, allowed the club a move back to this elite level after a 51-year absence."
And Mackay expressed his wish for his successor to enjoy a calmer tenure than he has had to endure.
"I would like to thank my players, all of my direct footballing staff, all the people behind the scenes at the club," he added.
"And most importantly the people of Cardiff, who have stood behind me resolutely throughout my time here and especially in these recent turbulent months.
"I leave with my head held high having gained a level of experience that, upon reflection, I suspect would have been difficult to find anywhere else in British football.
"The foundations laid at Cardiff City will provide a solid platform for my successor, and for the sake of the club, I hope that all of the progress that has been made so far will not be impaired in any way by today’s enforced changes."
Mackay leaves Cardiff 16th in the Premier League and facing an important home clash against basement club Sunderland on Saturday.
