Hirst won his first two Scotland caps after switching from England, where he played from U17 to U20 level.
“International recognition for us is still a special thing for us as a club and for the players because there are a lot of players like George who have been on the journey with us over the last few years,” McKenna told Sky Sports.
“So when you see someone like George making his senior international debut and doing well for Scotland in the couple of games in which he’s come on, everyone’s really proud of him.
“Having young talent at the club, if you’re talking about the likes of Liam (Delap), Omari (Hutchinson) and Jaden (Philogene) representing England U21s, having two goalscorers in Monday night’s U21 fixture from Ipswich Town in Jaden and Omari, I think these are really positive things for the football club. There’ some good signs there.”