Delon Armitage will complete a "massive turnaround" to his career when he starts for England in their opening Rugby World Cup game against Argentina on Saturday.
The London Irish full-back was dropped by England at the end of the 2010 Six Nations and he missed this year's title-winning campaign through suspension.
Armitage feared his chequered disciplinary record, which saw him banned last season for abusing an anti-doping official and for punching, would cost him a place at the World Cup.
But England kept the faith and a combination of Armitage's recent form and an injury to Mark Cueto has earned him a starting berth on the left wing for England's showdown with the Pumas.
"I didn't even think I'd be over here so it's a massive turnaround. If you do the hard work, the right things, sometimes you get your rewards," said Armitage.
"I'm really happy the way things have gone. When I was told by Martin that I would be starting he mentioned it was because of the way I'd been training and playing over the summer.
"It's massive satisfaction. To have the opportunity to start now, I'm speechless, it's like a dream come true."
Armitage was banned from the Six Nations for clashing with an anti-doping official after a London Irish game and he was in hot water soon after his return for punching Northampton fly-half Stephen Myler.
"What's happened has happened. (The England management) didn't really need to say anything to me. I just had to train hard," said Armitage.
"My record for England is really good, I've never had a problem or issues with discipline. There was nothing for me to really fix.
"I just wanted to keep doing what I'm doing for England and get some form back."
Armitage made his Test debut against the Pacific Islands in 2008 and enjoyed a flying start to his England career before injury and a chronic loss of form halted his progress.
"I play a lot better with a smile on my face, when I am relaxed and enjoying it and recently I have got to back that," said Armitage.
"The style England are playing, the way we want to throw the ball around and the way we want to have a go that suits the way we want to play."
Cueto is still struggling with the lower back injury which forced him off just 21 minutes into England's final warm-up international against Ireland.
Johnson insisted Cueto could have played in an emergency but Armitage's form, which brought him a try off the bench in Dublin, meant England had a simple decision to make.
Armitage will start a Test on the wing for the first time.
"Mark's had a little bit (of back trouble) before but he could have played (against Argentina)," said Johnson.
"There's a grey area between fit and injured in where most players sit all of the time.
"He trained fully all week, but he's not quite where he needs to be but the good things for us is Delon is playing very well.
"It's quite a simple decision. Delon been around for a few years now, we know when he is in form he is a Test match player. We've no qualms about picking him in any of the back three positions."
England's only other change from the Ireland victory is the return of number eight Nick Easter, who had missed the game with a tight calf, with James Haskell switch to the open-side.
Scrum-half Ben Youngs will make his international comeback off the bench after a knee injury ruled him out of England's three warm-up internationals.
England team to play Argentina in the Rugby World Cup at Otago Stadium, Dunedin on Saturday, September 10 (kick-off 9,30am BST):
B Foden (Northampton); C Ashton (Northampton), M Tuilagi (Leicester), M Tindall (Gloucester, capt), D Armitage (London Irish); J Wilkinson (Toulon), R Wigglesworth (Saracens); A Sheridan (Sale Sharks), S Thompson (London Wasps) D Cole (Leicester), L Deacon (Leicester), C Lawes (Northampton), T Croft (Leicester), J Haskell (Ricoh Black Rams), N Easter (Harlequins).
Replacements: D Hartley (Northampton), M Stevens (Saracens), T Palmer (Stade Francais), T Wood (Northampton), B Youngs (Leicester), T Flood (Leicester), M Banahan (Bath).