Petro Poroshenko, who was sworn in as president of Ukraine on Saturday, is a billionaire chocolate baron whose revolutionary zeal turned him into a political comet.
The pro-Western tycoon won an outright victory in a presidential election late last month with 54.7 percent of the votes -- a powerful mandate no one would have predicted just a year ago.
The emphatic victory was a much-needed boost for Poroshenko who takes the reins in the midst of the worst crisis between East and West since the end of the Cold War.
As if that challenge was not enough, he must also try to drag the country of 46 million out of a protracted economic recession.
"It is time for irreversible, positive change," he said after taking the oath of office in the Ukrainian parliament.
"To introduce change, we need first of all peace, security and unity."
The crisis with Russia has centred around Moscow's annexation of Crimea, a Ukrainian peninsula jutting into the Black Sea, as well as an uprising by pro-Russian rebels in the east of the country.
This pits Poroshenko against Russian President Vladimir Putin, whom he met briefly Friday as they both attended D-Day commemorations in northern France.
"The dialogue has begun, and that's a good thing," Poroshenko told Ukrainian television afterwards.
- Ukraine's Willy Wonka -
The tall, slightly greying tycoon is one of the country's 10 richest men with a fortune estimated at around $1.6 billion (1.2 billion euros) by Forbes magazine, which described him as Ukraine's Willy Wonka.
A shrewd politician who has flip-flopped between governments for more than a decade, Poroshenko was the only Ukrainian oligarch to openly back the pro-European protest movement that ousted president Viktor Yanukovych, under whom he served briefly as economics minister.
"Ukraine now returns to its natural European condition which so many generations have longed for," Poroshenko said in parliament on Saturday.
"The dictatorship that ruled Ukraine in recent years sought to deprive us of that vision, and the people rebelled."
Poroshenko was also the only politician to fly to Crimea in a bid to negotiate with pro-Russian troops who seized parliament after Yanukovych fell, but he was angrily chased off by demonstrators.
While ready to talk with Putin, he has insisted two issues are not negotiable -- Ukraine's pro-Europe direction and the status of Crimea.
"Crimea has been, is and will remain Ukrainian," he reiterated on Saturday to thunderous applause.
- Capable pair of hands -
Having held several cabinet portfolios and built strong links across the business community, he is seen by many as an experienced and capable pair of hands to stem an economy in freefall and unite the country.
He easily defeated his closest rival in the election, former prime minister Yulia Tymoshenko, whose association with Ukraine's corrupt political past led to her coming a distant second.
Unlike most of Ukraine's influence-wielding oligarchs who made a killing swallowing up state assets in the chaotic years that followed the Soviet Union's fall, Poroshenko's wealth is self-made.
He started out selling cocoa beans, buying up several confectionary plants which he later united into Eastern European candy giant Roshen that produces 450,000 tonnes of sweets a year, according to its website.
He also owns companies that make cars and buses, a shipyard and opposition television network Kanal 5, which broadcast live from Independence Square at the height of the revolution.
Poroshenko's fortune has however taken a hit from the current political crisis and the bitter standoff with Russia, a key market, which banned chocolate imports from his Roshen factory when Ukraine came close to signing of an EU association deal last year.
- Switching sides -
The married father of four was born in the small southwestern town of Bolgrad and studied economics at Kiev State University.
He entered Ukrainian politics in 1998 as a lawmaker for a grouping loyal to then-president Leonid Kuchma. He was one of the founders of Yanukovych's Regions Party in 2000.
But two years later, he changed sides after an election widely seen as rigged by Yanukovych.
Poroshenko joined forces with his close friend Viktor Yushchenko, who helped lead the 2004 pro-democracy Orange Revolution and later became president, making Poroshenko his foreign minister and chief of the central bank.
His time in office was controversial. A notorious falling out with Tymoshenko led to both of them being fired, and Poroshenko was also accused of abuse of power over the evaluation of a state metals firm, although the investigation was ultimately dropped.
In another switch, he was appointed as economics minister by Yanukovych in 2012. Later that year he was elected to parliament as an independent candidate and had hinted at running for mayor of Kiev before the current crisis.