The former Manchester City man has claimed that O'Neill helps the attacking players by fully backing them.
The 25-year-old is hoping to help the club progress even further this season and believes the support of O'Neill helps that.
"He stuck by me. He's one of the best man-managers around and he was keen to let us get on with it," said Johnson. "He didn't say any magic words, he just wanted to stick with us and urged us to stick through it.
"The gaffer knows attacking players have the most pressure on them to create or score a goal. He knew it would come. When we were struggling to score at the start of the season, the creativity gets blamed on the wingers. That doesn't bother me.
"We have to progress as a club like we have in the last couple of months. If we can keep winning games and moving up, then who knows where that can take us? For a player to be involved every week, that gives you some extra freedom. It does help to know the manager is sticking with you."
Johnson moved to the Stadium of Light in the summer for a fee of £12m.