Speaking to the press for the first time since taking charge, Moyes said that he owed a lot to the former manager for his role in bringing him to the club.
"I feel incredibly privileged that I was given the opportunity to manage Manchester United," Moyes said.
"I was grateful to Sir Alex and the board for making that happen. I knew nothing about the job until Sir Alex gave me the call and asked me to come to his house.
"I expected him to say he wanted one of my players, but the first thing he said was he was retiring and then he said, 'You're the next manager'. That was enough. I was shocked."