In November, Powell was removed from his position at the John Smith's Stadium, despite a relatively solid period for the Terriers in their previous nine games.
Huddersfield had recorded 12 points from nine fixtures, and the day before his exit, had earned a 2-2 draw at Reading, meaning that his departure from the club received a mixed reception.
However, in the midst of the disappointment that followed, the 46-year-old has revealed that former Manchester United boss Ferguson was one of the first people to ring him to offer words of encouragement.
Powell said: "I found out I was leaving Huddersfield and your phone rings because are sympathetic.
"My phone rang in the afternoon on a withheld number, but I answered it. A broad Scottish accent came on the other end of the phone and it was Sir Alex Ferguson.
"He said he was really sorry to hear what had happened, and that he had followed me and that I had done really well at other clubs. He said dust yourself down and you will be okay again.
"That was the godfather of management and he had called me. It was a great lift for me because obviously I was very disappointed."
Powell left Huddersfield with just 15 victories from 57 games in charge, but during the 2014-15 campaign, he guided the club to their best finish in the Championship since their return to the second tier in 2012.
His replacement David Wagner has won just seven of his 20 games in charge of the club, and he requires 16 points from their last 12 fixtures to equal Powell's tally last season.