Mr Key said his decisions were influenced by the failure of the Helen Clark-led Labour Government to rejuvenate fast enough, "and actually to promote the next wave of senior ministers".
Earlier yesterday, the Prime Minister referred to those ministers he promoted as the "next generation, I think, of leadership".
Mr Key has indicated he intends staying on as PM and National Party leader for this term at least.
Attorney-General Chris Finlayson holds his portfolio and his No 8 spot and picks up the Security Intelligence Service and Government Communications Security Bureau portfolios.
Although Ms Bennett said she was happy being in Cabinet for the time being, she did not rule out future leadership hopes.
"I think this kind of proves you never know what's just around the corner. If you'd asked me 20 years ago if I'd thought I'd be sitting on the front bench in a National-led Government, I'd have said no. So I don't know what the future holds. I just want to do the best I can now so that I've got options."
With the Justice portfolio previously held by Judith Collins, third-term Selwyn MP Ms Adams also picks up Courts and Broadcasting and holds on to her previous Communications role.
She said she had no ambitions to lead the party.
"I can honestly say that at the moment it's not something I'm aiming for. Simply because I look at the job John Key has to do, the size and scale of it and the bar he has set and I'm just not sure it's something at the moment that I have any hankering for. I'm not sure I want to put my hand up for that."
Watch: John Key unveils new Cabinet line-up
Mr Bridges said Mr Key had given him a sense of what he could expect "but it's even better than I thought".
He avoided the leadership question, saying Mr Key was "a very special Prime Minister and I think we've got him for some time to come".
"I've got no doubt he is going to lead us into the next election and all of National's MPs, certainly the front bench, will be working ceaselessly to see him back for a fourth term even though that's a challenge."
Dr Coleman said the Health portfolio was a good fit with his former career as a doctor and he intended to follow Mr Ryall's successful slow but steady approach.
"Tony has managed the portfolio excellently so I think it would be foolish to make any sudden massive changes. And I think he has laid down a good template for the management of health."
Dr Coleman said areas he would focus on included the long-term challenges of diabetes and obesity.
The potential to tackle obesity through more active lifestyles was cited by Mr Key as his reason for also giving Dr Coleman the Sport and Recreation portfolio.
As well as picking up Transport, former lawyer Mr Bridges keeps his previous Energy and Resources portfolio - a combination that is likely to ensure he is even more a target for the Green Party than before.
He said the two came together well in the infrastructure area, adding that his environmentalist critics might be surprised by his approach.
While the Government was committed to building roads and petroleum exploration, "I want to do a lot of work in renewables for energy".
"For transport, we will continue to do work in conventional transport networks but I think you'll also see us surprise a few people in some of the things we do in areas such as cycling and potentially other areas."
Other winners included second-term MP Maggie Barry, who was fast-tracked into the Cabinet as Minister for Arts, Culture and Heritage, Minister of Conservation and Minister for Senior Citizens, and Todd McLay, who retains his Revenue portfolio but is promoted into the Cabinet.
Third-term Maungakiekie MP Peseta Sam Lotu-Iiga, who was already a minister, gets Corrections, hangs on to his renamed Pacific Peoples portfolio and is also promoted, rising five places into Cabinet.
Mr Key said Ms Barry had a lot of expertise and experience relevant to her new portfolios
"Obviously they're big calls to make when you pick one person in the 2011 [intake] and make them the first one that goes into Cabinet but I think she's going to prove herself to be a very strong minister."
The biggest losers yesterday were Craig Foss, who loses his place in Cabinet and his Commerce role for a handful of lesser portfolios, and former Courts Minister Chester Borrows, who is no longer a minister.
Mr Borrows admitted he was disappointed not to get another term "to strut my stuff" as a minister but said getting the nod from Mr Key for the Deputy Speaker's role was some consolation.
He is likely being prepared as a potential replacement for current Speaker David Carter if Mr Carter leaves this term or at the next election.National's Epsom candidate, Paul Goldsmith, is a new addition to the ministerial ranks, getting Commerce and Consumer Affairs. Although he did not manage to go straight into the Cabinet like Maggie Barry, he will take some solace from being ranked higher than Act's Epsom MP, David Seymour, who is a parliamentary under-secretary.
Mr Goldsmith said he did not see his elevation as a reward for agreeing not to campaign for the electorate vote in Epsom to ensure Mr Seymour won the seat, saying the Prime Minister had not even mentioned it to him. Mr Key made it clear an elevation to Cabinet was likely in future.
Winners
Paula Bennett: Takes over from Judith Collins as National's highest-ranked woman.
Amy Adams: Canterbury lawyer rockets up from 15th place straight on to the front bench in 7th and gets the Justice portfolio.
Simon Bridges: Shoots up from 18th to 9th and on to the front bench, as well as picking up the Transport role and Deputy Leader of the House.
Jonathan Coleman: Gets the Health portfolio and front-bench ranking. Health was once the poisoned chalice for any minister, but Tony Ryall turned it into an asset.
Chris Finlayson: PM's level of trust clear from appointment of Finlayson as Minister for GCSB and SIS - a role the Prime Minister traditionally holds alone.
Honourable mentions
Maggie Barry: Straight into Cabinet as Arts and Conservation Minister in second term as MP.
Paul Goldsmith: Minister outside Cabinet, National's obedient Epsom candidate is at least ranked higher than Act's Epsom MP, David Seymour. Not quite ripe, but future looks bright.
Nikki Kaye: Up four places, picks up ACC.
Michael Woodhouse: Up three places, gets Immigration, Police and Workplace Relations portfolios).
Peseta Sam Lotu-Iiga and Todd McClay also make it into Cabinet.
Losers
Craig Foss: Sent a clear signal to pack his bags by 2017 - dumped out of Cabinet, loses Commerce and gets Small Business and the Statistics portfolio usually reserved for ministers in training.
Hekia Parata: Holds Education but bumped off the front bench into 10th place. On a last chance to prove herself.
Chester Borrows: Loses ministerial portfolios but gets Deputy Speaker.
Last chance
On last-term warnings - Murray McCully, Tim Groser and possibly Nick Smith, who remains well adrift of his former front-bench post.
