Ten years on however, he has defied the odds, surviving and the temporary loss of two thirds of the national territory to into relevance and hold on to power.
It seemed doubtful in March 2011, when protests broke out in Syria, that his ruling Alawite minority would be capable of withstanding the tide of uprisings dramatically reshaping the region.
The leadership mettle of the London-trained ophthalmologist, a reluctant heir when his father Hafez died in 2000, was also being questioned.
But his patience and cool combined with myriad factors - including his grip on the security apparatus, the West's disengagement, and the support of - to save him from defeat, analysts say.
"Years after the whole world demanded he leave and thought he would be toppled, today it wants to reconcile with him," veteran Lebanese politician Karim Pakradouni said.
'Long game'
"Assad knew how to play the long game," said the politician, who has often acted as a mediator between the Damascus regime and various Lebanese parties.
In 2011, Assad on peaceful protests with force, sparking a complex war involving rebels, jihadists and world powers in which any fighter not on his side was called a "terrorist".
The conflict has since , displaced more than half the country's pre-war population, and seen tens of thousands thrown behind bars.
Ordinary Syrians have seen food prices soar and the local currency plummet in a desperate economic crisis the government has blamed on Western sanctions.
But Assad is still in power and, after a string of Russia-backed victories, his forces are back in control of around 70 percent of the country.
The Syrian president always insisted he would come out on top.
"He has never faltered. He has stood firm on all his stances without concession, and has managed to take back most of Syria with military might," Pakradouni said.
Loyal army
Despite tens of thousands of defections, Syria's army also played a major role in his survival, he said. "This is what made Assad an exception in the so-called Arab Spring."
In Tunisia, the army abandoned Zine El Abidine Ben Ali when street pressure mounted, Egypt's military also let go of Hosni Mubarak, and in Libya, top brass had already turned against Muammar Gaddafi before his demise.
Analyst Thomas Pierret said: "Army leadership remained loyal because for decades it had been stacked with relatives of Assad and fellow Alawites".
"The latter probably made up more than 80 percent of the officer corps by 2011 and held virtually every single influential position within it," said the researcher at the Institute of Research and Study on the Arab and Muslim Worlds.
A Syrian researcher based in Damascus who asked to remain anonymous said Assad's "determination and rigour" were also key.
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"He was able to concentrate all decisions in his hands and ensure the army was entirely on his side," the researcher said, adding the regime's structure ensured nobody could build up enough influence to tee up a challenge.
Instead, Assad gambled on Syria's complex social structure - between Arabs and Kurds, as well as religious differences between Sunni Muslims, his Alawite clan, and other minorities.
"He benefitted from people's fear of chaos, from his own (Alawite) environment's fear about their survival if he fell," the Syrian researcher said.
No alternative
When Islamists and jihadists became more prominent, he sought to present himself as a protector of minorities including Christians.
But Assad also benefitted from the absence of any effective political opposition, the researcher said.
In 2012, as Assad's forces were losing on the ground, more than 100 countries recognised an opposition alliance, known as the Syrian National Coalition, as the sole legitimate representative of the Syrian people.
Assad appeared increasingly isolated and many regional and world powers, betting on his downfall, slapped his regime with a raft of sanctions and turned him into a global pariah.
But Syria's domestic and exiled political opposition failed to present a united front, or a credible alternative to Assad with which the international community could engage.
The armed opposition became increasingly fractured as the conflict evolved, and Assad was able to instrumentalise the rise of jihadist groups to cast himself as a rampart against terrorism.
US failure to use force
The rebels needed air power to help them, but the West wanted to avoid a Syrian repeat of the NATO fiasco in Libya.
As years went by, Assad grew increasingly confident that no US warplanes would come anywhere near Damascus.
In 2013, following an alleged regime chemical attack on two rebel-held areas outside Damascus that killed more than 1,400 people, then US president Barack Obama balked at air strikes to punish the crossing of a "red line" he himself had set.
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"The Obama administration was not interested in the Syrian conflict," Pierret said. "It had been elected on the promise that it would withdraw from Iraq, hence was reluctant to return to the Middle East."
A US-led coalition did launch strikes in Syria the following year, but that was to back Kurdish-led fighters battling the Islamic State group whose newly-proclaimed "caliphate" had become the focus of global attention.
Russia stepped in the year after in support of Assad and launched its first air raids in 2015, turning the tide of the conflict.
It "seized a historical opportunity to retrieve its lost superpower status by filling a strategic void left by Obama's partial disengagement from the region," Pierret said.
'Impossible equation'
Once clamouring for Assad to leave, Western powers are now eager for a political solution to stem the conflict before presidential elections next summer.
"Today the Syrian regime cannot be accepted back into the international system, but also cannot remain outside it," the Damascus-based researcher said.
"This impossible equation will leave us in a quandary for years to come, without solution or stability," he said.
Without a political solution to unlock international reconstruction funds, the Syrian people will continue to pay the price of the country's "slow bleeding out", he said.
Assad is already in his third decade in power at 55 and a fourth mandate in 2021 looks all but guaranteed, as tens of thousands of the Syrians who peacefully protested to demand his removal almost a decade ago are now exiled, jailed or dead.
Agencies contributed to this report.
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