He sent troops to Iraq against stiff opposition in Paris and Berlin, rejected the Euro as fellow leaders embraced economic harmony and angered neighbors by playing hardball over the European Union budget.
So why is Tony Blair emerging as a candidate to become Europe's first president?
The former British prime minister, who led his nation for 10 years and won three successive elections, has been touted as a strong contender for the post of EU president -- a job being created under a new EU treaty that aims to streamline the bloc's often complex decision-making.
Blair's dynamism
While some claim Blair's dynamism would help push the continent's interests with the U.S. and emerging economies of China and India -- others fear his appointment could trigger a new round of internal bickering after years of rancor over institutional changes.
"Blair and international politics have not seen the last of each other," said British lawmaker Denis MacShane, Blair's Europe minister from 2002 to 2005.
Blair's spokesman Matthew Doyle declined to say if Blair, still in his new role as Middle East envoy, has ambitions to take up the EU job.
"There is no campaign and no campaign team. Mr. Blair is focused on his role in the Middle East," Doyle told The Associated Press.
Blair himself has declined in recent interviews to rule out a run for the post.
The Briton has won favor in France, where President Nicolas Sarkozy has suggested both Blair and Luxembourg's leader Jean-Claude Juncker as candidates, and among his loyalists in London, who long to see him return to the political center stage.
But elsewhere on the continent a campaign dedicated to halting Blair's bid before it officially starts is gathering widespread support.
'Stop Blair' petition
A "Stop Blair" Internet petition launched by a group of European bloggers has attracted around 4,000 signatures since it was posted Tuesday, while a statement opposing his candidacy has been translated into nine languages.
"His role in the Iraq war would weigh heavily on the image of the (European) Union in the world," a statement by the European Tribune group said. "We declare our total opposition to this nomination."
But it's not just European citizens, or opponents of the Iraq war, who oppose Blair taking Europe's helm.
Many of the European Union's 27 members also worry over a figure from Europe's big three _ France, Germany and Britain _ taking on a role at the head of the EU, particularly a figure from the famously euroskeptic U.K.
Candidates will need to put themselves forward to be considered for the job, which will have a maximum five-year term. British officials said so far no one has declared an interest.
"No one is going to put their name forward without knowing they have the support," MacShane said.
The appointee will be selected at the same time leaders chose a new EU foreign policy representative, a new chairman of the European Commission and chairman of the European Parliament.
Defining job
Though the EU president role will involve chairing meetings of national leaders, many think the first incumbent will largely define the job. Antonio Missoroli, director of studies at the European Policy Centre in Brussels, Belgium, said some fear Blair would demand too much power and could attempt to seize control of Europe's policy agenda.
"Some EU countries are dead against Blair _ and they don't see why a U.K. official should lead Europe when Britain is so marginally involved in a number of common policy areas," Missoroli said.
He said many members believe there is an unwritten agreement to allow a candidate from a smaller nation _ such as Juncker's Luxembourg _ to take the post.
The new EU president will replace a current system of rotating six-month presidencies shared by each member country and be selected by the leaders of the European nations.
Diplomats privately concede Blair is handicapped by the U.S.-led Iraq war _ which was hugely unpopular with Europeans _ a factor that Missoroli said could be decisive.
His legacy as the staunchest ally of President Bush also rankles with many on the continent.
"Blair became a hugely divisive figure because of Iraq, these things are not said in public, but they linger on in the background," Missoroli said.