Birmingham put Shotton at the top of their wishlist at the start of the most recent transfer window, but it looked as if they were going to miss out on signing the former Stoke City defender.
However, after Derby completed some incoming additions in January, Paul Clement was more relaxed to the idea of Shotton leaving, which enabled Birmingham to tie up a deal.
"Ryan Shotton was pretty close to being our number one target in his position also," Rowett said.
"I asked about him a couple of times during the window and got a flat 'no' off Derby but this time there was a little bit of movement because of the players they brought in.
"I’m pleased because we were able to fill the areas we wanted and they are players that want to come in and do well for various reasons."
Shotton is only on loan at Birmingham for the rest of the season, but he will be hoping that his time at St. Andrews sees him feature more than he did back at Derby.
Shotton increases Birmingham’s options in defence considerably, as he can cover right across the back line. That could be crucial for the Blues, who have one of the smaller squads in England’s second tier.
Shotton could make his Birmingham debut against Sheffield Wednesday on Saturday.