"There was no major change in him the day after we lost 7-1 at Norwich to when we won 3-1 at Aston Villa," the Wales international said.
"He's never massively high or massively down, he just creates a constant message and as a player, that's great."
Third-placed Reading face Gunter's ex-club Nottingham Forest on Saturday.
The 27-year-old has taken on the responsibility of captain in the absence of Paul McShane in recent games.
"Not too much really changes," he said. "It's not a case of just because you start wearing an armband, you start acting differently.
"That's probably not why you've been handed it in the first place. Things stay the same and it's a nice thing to do and even nicer when you win."
Reading can guarantee a play-off place with victory at relegation-threatened Forest and Gunter believes it is no more than their consistent performances have merited.
"More often than not, it's been tough for opponents against us," he said. "We haven't blown teams away by winning four or five-nil each week, but for large parts of games, we've been in complete control.
"We've played some really good football and we deserve to be exactly where we are."
Reading defender Chris Gunter believes Jaap Stam's consistent approach in management has helped to maintain their Championship play-off push.