He was visibly delighted when his old friend Bill Clinton, the former US president, introduced him at the launch of Mr Blairís new Faith Foundation.
"I have learnt that there's not only life after politics," Mr Clinton said.
"There's also good life, if you find something you truly believe in. [Mr Blairís] found something he believes in."
There are those who will be cynical about Mr Blair's new project.
There will be plenty who will wonder whether a man so many associate with war is the best person to try to foster global peace and understanding.
Battle of faiths
It is obvious however - when you speak to Tony Blair about the subject - that this is indeed something he is very driven about.
This isn't an incidental or second order issue, this is fundamental to how the world develops
"It is a massive undertaking, but how important is it? If all the good tunes are with the extremists Ö if they're the ones out there with the strong message and those of us who believe that religious faith is about peaceful co-existence are silent we've got a real problem on our hands," he said.
"This isn't an incidental or second order issue, this is fundamental to how the world develops."
In short, Tony Blair believes that faith is the new battleground.
He believes it's been hijacked by extremists - from all religions, he's careful to say.
Faith, he says, needs to be claimed back by those who believe in co-existence.
This is a huge departure for a man who as prime minister was reluctant to speak of his faith.
I never hid the fact that I had religious convictions
In the US and other countries it is almost a political obligation to do so. It isn't in Britain.
"When I was PM to talk about religious faith in the British context is more difficult. It has complications.
"I never hid the fact that I had religious convictions - but what I want to do now is focus on how we bring greater understanding between the faiths," said Mr Blair.
In New York there were congratulations for the education projects envisaged, and for the multi-faith work that is proposed on combating malaria and poverty.
Can it work? That is the big question.
Those who have closely followed Mr Blair in recent years often say he's good on the theory, the grand ideas, less good on the detail.
This though is a project that he envisages lasting several years, if not decades.
Tony Blair hopes to unite the world's religions
It is, he says with a shrug, perhaps what he plans to concentrate much of his energy on for as long as it takes.
He also clearly believes it is not only a vital project, but one that will yield results.
"Iíve found out in the [Middle East] region actually a tremendous desire and willingness to engage with the notion of inter-faith understanding...
"People see that as an important part of creating the context of which their countries can engage with the modern world, because the modern world is all about peaceful coexistence," he said.
There's nothing new in these ideas of course, but in setting up his foundation, Mr Blair is hoping to wrestle the initiative back from the religious extremists who so often dominate todayís news agenda.
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