Stimson took over in November 2007 and was unable to prevent the club from relegation last season as he began an overhaul of his playing staff, but he has guided the Gills to Wembley this time around.
And Scally told the 'Coca-Cola' Football League podcast: "I had a difficult couple of years, but getting hold of Mark Stimson a year and a bit ago now was a massive coup for me because personally I like the guy and secondly I believed he could take us back to where I think we could comfortably be as a club.
"It's taken him a bit longer to do that than perhaps he thought but then he did have a lot of issues to sort out when he came to the club.
"It's nice now to start to see things turn for him and for the players he's brought in - some of them have come out of the Conference. I'm really pleased to a man how well they've all done.
"He just wants players to be honest and strong and work hard and I think he likes to play football and the football we've seen this year from the team has been fantastic."