But blunders and scandals have turned the 51-year-old into a “lame duck”, experts say, all but destroying his chances of leading the Social Democrats (SPÖ) to victory in Sunday's elections.

Newspapers that had hailed his nomination in May 2016 as a “new chance” now warn of a “fiasco”.

The Social Democrats look set to be consigned to the opposition for the first time since 2000, outflanked by increasingly hardline conservatives led by 31-year-old Sebastian Kurz.

And yet it had all started so promisingly.

Articulate and telegenic, Kern seemed the ideal candidate to reboot the SPÖ after its disastrous performance in last year's presidential race, which had claimed the scalp of Kern's predecessor Werner Faymann.

“We need to open the windows and let fresh air in,” Kern urged in his first official speech.

Impeccable credentials

With his working-class background and business acumen, the father-of-four had impeccable credentials on paper.

The son of an electrician and a secretary, Kern joined the SPÖ following a brief stint in journalism after university.

A first-time dad aged barely 20 — “My partying days were quickly over,” he said in a recent interview — he swiftly moved up the ranks and became a much-praised spokesman in the government of Franz Vranitzky.

In 1997 Kern left politics to pursue a stellar business career, first as senior manager at the country's biggest electricity company, then as popular boss of Austrian Federal Railways (ÖBB).

By the time he became chancellor, his working class accent had gone, talking, the Austria Press Agency said, “as if he had grown up in Schönbrunn Palace” — Vienna's former imperial summer residence.

'Vain princess' 

But the euphoria over the social media-savvy Kern, whose suave appearance earned him comparison with Humphrey Bogart, was short-lived.

For one he failed to resolve the SPÖ's internal rifts, especially over whether to cosy up to the far-right Freedom Party (FPÖ), set to become junior coalition partners to Kurz's conservatives.

“Even a prime candidate like Christian Kern won't be enough” to save the SPÖ, said analyst Hubert Sickinger.

Embarrassing revelations also chipped away at Kern's polished image.

A SPÖ promotional video of him posing as a pizza delivery man to listen to ordinary voters' concerns turned awkward after claims that the stunt had been staged.

In September an SPÖinsider called Kern “vain” and “a princess” in a leaked report.

Most damaging was the departure of the party's number two this month over allegations that a shady spin doctor masterminded an anti-Kurz smear campaign in the name of the SPÖ.

Although Kern denies all knowledge, the scandal has given his rivals plenty of ammunition.

“Kern has dominated the debates… for all the wrong reasons,” commented analyst Wolfgang Bachmayer. “He's a lame duck.”

Kern has vowed to go into opposition if his party doesn't come first.

But there are doubts he'll still be leader at all after Sunday.