The Canaries are now flying under Hughton this season.
"He has brought stability. He has made us harder to beat and you can see that from the goals conceded," Johnson told the Pink 'Un.
"He is very keen on keeping clean sheets and now we don't look like we are going to concede goals in games. The manager has come in and seen last year perhaps that we are conceding a lot of goals.
"I think last year we had a motto of 'you score, we score' which probably wasn't good, even though we did well last year, but the manager has come in and brought some new players and they have done brilliant for us. I think the fact that we are keeping clean sheets is good and now we just have to score a few more."