The former Scotland manager was speaking as part of Sky Sports' The Debate panel when he made the claim.
He revealed that he would sign the recently released former Manchester City footballer claiming Johnson needs to "make a living for himself and his family".
Strachan said: “I would if he’s shown genuine remorse. Then I’d say, ‘right, let’s get on with it’.
“I would because I go back to what I believe in that everybody deserves a second chance – and he’s done his bit. People will think he’s done his three years – but this is for life. People will say ‘that’s that guy’.
“But he also still has to make a living for himself and his family. What if we don’t allow him back in the game and his family are affected? His kids? We’ve got to think about that.
“You cannot destroy his family and himself just because of what he did. He’s done his three years. We must forgive. I generally think we forgive most people if they show remorse.”
Gordon Strachan was speaking alongside former England manager Sam Allardyce who concurred with the Scot.
Allardyce said: "A lot of people will disagree with that, but will he get back into football? It’s difficult to have three years out and actually play football again.
"So, at the moment it’s a big question mark about whether he can reach the level of professional football again when, psychologically, (you don’t know) what damage it’s caused him, let alone physically.
"He’s served his time and he deserves to do whatever he does, wherever he can.
“He will get obstacles in football where people will not want him to be at their club. That’s happened before."