The former Newcastle United, Celtic and Aberdeen forward did some scouting on Mackail-Smith for Scotland boss Craig Levein last season and since his selection in the national team, McGhee feels he has excelled and is backing him to become a Scotland star.
"Around the camp he is excellent. They really like him and it seems to be the same at Brighton in the type of boy he is," said McGhee.
"As I understand it, he's not a cocky type but determined to do well for club and for Scotland.
"He sees he's been given a wee chance with Scotland to go to the next level and he wants to impress. He doesn't let things intimidate him.
"He's scored a goal for Scotland, which gives him a kudos with the supporters. And he'll be the kind of guy team-mates like because he grafts away.
"He's dependable in that sense and they'll appreciate that about him.
"Brighton are a passing team, but he's something a bit different. He has a work ethic and he's the livewire.
"When he was at Peterborough he was a bit of a cult hero because of his attitude and I can see it going the same way at Brighton."