Eaden became Redfearn's number two on Thursday, signing a two-and-a-half-year deal and replacing the departed Eric Black.
It's his second spell with the Millers after a brief stint in 2011 and he leaves his position as Leicester's Under-21s coach.
Redfearn, who played with Eaden at Barnsley in the mid-1990s, insists Eaden's experience and philosophy will be beneficial to the club.
"He's got real experience of the Championship," the Millers boss said. "He's got a good coaching background and he's been an assistant manager at Peterborough.
"He's got experience of developing young players, which is really key because my remit when I first came here was to make these players better and stay in the division.
"He understands this division. Eventually we want this club
challenging at the top end of this division and getting into the next one.
"We
know it's going to take time but we know it can be done.
"If you've got the
right people at the club who know the route, then you've got a better chance of
doing it."
