The Scot insists the deal was right for both the player and the club, and is now targeting further additions to his squad before the close of the transfer window
The England international had been linked with a move away from Goodison Park ever since bursting onto the scene as a highly rated 16-year-old in 2007.
But, after keeping hold of the midfielder despite reported interest from Manchester United in the past, Moyes allowed the player to join City on Sunday.
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"I had known about it for a while and I thought it was something that was right for Jack and right for Everton," he told reporters.
"It was something which I felt at this moment in time was right.
"It gave Jack an opportunity to go to a really good club and take his chances there.
"It gives us a chance to do a little bit more business in the transfer market having raised the money. Hopefully I will try to add to the squad before the season starts."
Unlike previous years, where the likes of Wayne Rooney, Joleon Lescott and Mikel Arteta have been sold to bring in funds, Moyes insists the club were not in a position where they had to sell Rodwell.
The Toffees boss said: "Last year we had to do it, this year we didn't have to do it as we had already sold Tim Cahill and Joseph Yobo.
"It wasn't a necessity to do it this year but I felt it was the right thing and gave us a chance to have a look around to see what we could do.
"We are out there actively trying to bring in another couple of players at least."