In an interview with Yahoo! Sports, Newton says he had difficulty adjusting to losing during Carolina's 6-10 season.
"I was very immature," Newton told Yahoo! of his reaction after losses. "I'll be the first one to tell you, the pouting and the moping, I kind of overdid it. I know that. I was a bad teammate. I shut off to some people who gave unbelievable effort. ... That's where I have to mature."
The multi-talented quarterback who took the NFL by storm a year ago, teaming with wide receiver Steve Smith to take the previously powerless Panthers' offense from the league's worst in 2010 to the fifth highest scoring attack in 2011.
But Newton, who became the first player in NFL history to pass for 4,000 yards and run for 500 last season, said he would let an interception or bad play eat at him during games and after losses.
"Half the time it wasn't me shutting people down because I was thinking they weren't giving the same effort as me, it was me knowing there were things I could do that could have changed the outcome of the game," Newton told Yahoo!. " ... I put a lot on me to be able to respond. When things are going wrong, I wanted to have the ball in my hand, just like any warrior, any competitor who has played this game. When you don't get the results you want, I didn't go about it the right way."
Smith, who saw his career revitalized by Newton's arrival, says the multi-talented quarterback just needs to understand he has teammates who can help him, if he lets them.
"Cam was angry because he thought he could and should make every play," Smith told Yahoo!. "He has to realize you can't do it all yourself. It's like when someone drops a touchdown pass at the end of a close game. You can say that play cost the team a chance to win the game, but it didn't cause the team to lose.
"As you get older in this game, you see how everybody has to do their job and how there are so many plays in a game that affect the outcome. As a competitor, you want the ball in your hands at the end to make the play, but you can't do it all in football. You have to give other people a chance to make a play for you, to help you out."
Newton told Yahoo! the key for this year is to better manage his emotions during games.
"I have to have the same mentality, but I have to go about it in a different way," Newton said. "It's an overall maturity level that has to kick in. It's saying, 'OK, that was two plays ago that you threw that interception, now you have to let that go and get past that.' I can't be moping and crying about making a bonehead play when it was three series ago. That's the thing that I did that has to change."
Coach Ron Rivera said during one of Carolina's organized team activities that he's seen Newton take on a leadership role through the way he's interacted with teammates and encouraged them during offseason conditioning drills.
"He's really maturing and becoming what you hope for in your starting quarterback," Rivera told The Associated Press on May 24. "You're seeing a continued evolution based on what happened at the end of last year."
That only adds to the optimism gained from the Panthers overcoming a glut of injuries on defense early last season and rallying to win four of their final six games.
"My fingers are crossed and my knees are on the floor every night just praying and just demanding that people watch the show and see what happens this year. Just watch the show," Newton told Yahoo!.
Information from The Associated Press contributed to this report.