Jean-Claude Juncker - Europe's longest serving leader

Luxembourg Prime Minister Jean-Claude Juncker, Europe's longest-serving leader, looks set to extend his 18 years running the EU's wealthiest nation, though his popularity is sliding, according to estimates from elections Sunday.

A staunch defender of the euro and the European dream, Juncker faced a snap election after being accused by parliamentarians in July of putting the single currency ahead of the small nation's domestic problems.

A parliamentary inquiry into the country's intelligence service -- the SREL -- found Juncker had been too busy steering the euro through crisis to oversee the shady doings of his agents.

In January he ended eight tumultuous years at the head of the Eurogroup, which oversees the currency shared by 17 European Union nations.

But voters appeared to scold Juncker for having taken his eye off domestic issues.

His conservative Christian Social People's Party party won 33.4 percent of the vote and 23 seats in the 60-seat parliament, according to estimates by RTL television. That was down from 38 percent and 26 seats in 2009.

Juncker, aged almost 59, is known for his dry sense of humour, commitment to the European cause and ability to reconcile the often sharply differing views of France and Germany, the bloc's top two economies and his country's neighbours.

"When I want to speak in French, I think in German; when I want to speak in German, I think in French, with the result that I am totally incomprehensible," he once joked.

Juncker first joined the Luxembourg government in 1982, when only 28, and has sat at the top table ever since, serving as finance minister, then as premier from 1995, becoming a fixture on the 28-nation European Union scene.

He has "two fatal flaws -- he has an opinion and he is not afraid to share it", said one European official.

In a farewell address to the European Parliament as Eurogroup chief this year, Juncker typically did not mince his words, railing against unnamed, rich northern states that he said had become arrogant, laying down the law to their weaker southern EU partners.

None of the strains of the euro crisis dampened his faith in a federal European state that could be home to all its peoples and traditions after centuries of conflict and bloodshed.

Juncker was born December 9, 1954, in a Europe still struggling to rise from the wreckage of World War II, when his father was press-ganged into the German army.

His father was a strong influence, not least for his experiences as a metal worker and union member.

A smoker, Juncker appreciates the finer things in life -- good cognac, certainly -- and holds firmly to the political right but is suspicious of the simple idea that free market economics can solve all problems.

"Juncker, he is the most socialist Christian Democrat there is," said MEP Daniel Cohn-Bendit, leader of the Greens in the European Parliament.

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