Blues have spent months negotiating with Rowett over an improved deal in the hope of warding off any interest from sides in the Premier League should they come calling.
The former Burton Albion boss has now signed a one-year rolling contract with Birmingham, while backroom staff Kevin Summerfield, Mark Sale and Kevin Poole have all been handed improved contracts.
The St Andrew's outfit are currently just two points off the play-off places and Birmingham director Panos Pavlakis says the new deals for the coaching staff is a demonstration of the club's commitment to getting back into the Premier League.
"We wanted to show our support and commitment to Gary, Kevin and his coaches for the work that has gone on and these new contracts are a significant development in that respect," Pavlakis said on the club's website.
"We have had a fantastic relationship with Gary since day one. He is very happy here and we share the same vision in continuing to move the team and the club forward."