After a strong start to the season in the Heineken Cup and RaboDirect PRO12, Scott stood out once more as Scotland saw off Japan 42-17 at Murrayfield on Saturday and Johnson reckons he will only get better as his career progresses.
"He is a special kid and a special player and I think he can go further in the game than we are willing to admit," said Johnson.
"It's well documented what I think he can be: he is not there yet but he is going to be a special player. The sky is the limit.
"He is a wonderful athlete with good skills and good feet - that's a lot of boxes ticked there. I am glad he is playing for us: I will be incredibly glad in a couple of years' time because I think the world will be talking about him."
Scott is still a relatively new name on the international scene given that he only has 15 caps to date but he is fast earning a reputation as one of his country's most dangerous weapons.
He only made his Heineken Cup debut in the 2011/12 campaign yet he was a key figure in helping Edinburgh reach the semi-finals for the first time that season.
The Dunfermline-born midfielder scored a crucial try in Edinburgh's shock win over Munster in this season's Heineken Cup opener and he was badly missed by Alan Solomons' side the following week when he sat out the defeat at Perpignan.
He is a doubt for Scotland's clash with South Africa this Saturday, though, after suffering a hand injury in the closing stages of the six-try thrashing of the Japanese.
There is no suggestion that he would be forced out of Edinburgh's European double header with Gloucester next month but Johnson and Scotland doctor James Robson admit he may have to watch this weekend's Test from the sidelines.
"Disappointingly, he has been banged up on the last play there and it was the one thing we wanted to get him through to the end. But it opens the door for somebody else probably," added Johnson.
"Matt requires further assessment before we can ascertain the full extent of his injury. As ever with soft tissue damage it can be 48 hours after a match before the scope of any injuries becomes clearer," said Robson.