Bowyer scored the only goal of the game against his former club that earned Blues their fourth successive Premier League win and moved them up into eighth place in the table.
"Lee has thrived on the atmosphere at this club and you ask any player when they're in good form they say the whole ambience is fantastic," McLeish told Sky Sports after Blues' 1-0 win at St Andrews on Saturday afternoon.
"He's playing with a lot of freedom but he's shown every ounce of experience in the game.
"He's not got caught in possession, he's use of the ball is great, his tackling is great and those timing of runs into the box he's famous for."
McLeish also reiterated that despite Blues stretching their unbeaten run to seven games they have to stay focussed on the challenges ahead.
"I have to keep my feet on the ground and keep the players' feet on the ground," the Blues boss added.
"I thought again they passed another test today.
"The expectations after each good performance rises and the players have to handle that.
"But I know the character of the players that I've got in the dressing room and it certainly warms the heart when you know can trust players."