A wave of protests in Hong Kong ahead of citywide elections is posing a major test for the new leader as the prospect of voter discontent threatens to shake up the political landscape in retaliation against perceived meddling by Beijing.
This time round, the legislature will have a more democratic flavour - it has been expanded from 60 to 70 seats, with just over half of those to be directly elected in Sunday's polls.
The results are likely to reflect the anti-China sentiment, especially over a school curriculum plan extolling the achievements of the Chinese Communist Party.
Thousands have demonstrated outside government headquarters around the clock for a week demanding the school programme be scrapped and forcing Leung to cancel what was to have been his first major international engagement as leader at the APEC forum in Russia.
Schoolchildren, teachers, parents and ordinary citizens have denounced the curriculum as Communist Party propaganda glossing over the darker aspects of Chinese rule, hitting a raw nerve in the former British colony that remains proud of its freedoms 15 years after returning to China.
The protests have included hunger strikes and the parading of a replica of the Goddess of Democracy statue outside government offices, invoking memories of the June 4, 1989, Tiananmen Square uprising in Beijing and throwing the spotlight on a new generation of activists determined to have their say.
"He (Leung) feels that just by repeating the same lines, the problem will go away. But Hong Kong civil society doesn't work like this anymore," said Lo Chi-kin, a public affairs consultant.
"These post '80s and '90s young people will not just go away after hearing the government utter the same old lines.
"They really want a part in the decision-making process... and if you don't give them an equal chance at being a part of that process, the only way is for them to take to the streets."
ANOTHER HEADACHE FOR BEIJING
Hong Kong is a freewheeling capitalist hub which enjoys a high degree of autonomy, but Beijing has resisted public pressure for full democracy and has maintained a high degree of behind-the-scenes influence in political, media and academic spheres, among others.
The latest uproar represents yet another headache for Beijing, after Chinese President Hu Jintao appealed in July for Hong Kong to maintain unity, with Beijing's own leaders grappling with their imminent leadership transition after the controversial ousting of former party heavyweight Bo Xilai.
Although the outcome of Sunday's election will not affect Beijing-backed Leung's position, political analysts say recent controversies may benefit the opposition pro-democracy camp, making it more difficult for the chief executive to pass policies in a fractious legislature in coming years.
Leung would be the biggest loser in the election whatever the outcome, with the polls coming when the city is torn by suspicion and mistrust, said Baptist University professor Michael DeGolyer, who has been charting public attitudes toward China since the 1997 handover.
"Can we trust this government? Can we trust its abilities? Can it rule? These are the questions that lots of people will be coming out to vote for," DeGolyer said.
In a move that signalled a softening of the administration's stance on the education programme, a government advisory body said on Thursday it was willing to discuss and possibly compromise on the scheme.
Hours later, Leung also sought to reassure residents angry over high property prices and a yawning wealth gap, pledging to start land sales for property restricted to Hong Kong residents from the first quarter of 2013.
Insults have been hurled both ways across the border this year, with Hong Kong residents blaming a flood of Chinese visitors to the city and mainland Chinese countering that Hong Kong for too long has looked down on its cross-border cousins.
Earlier this week, Leung said China had put off a plan to allow millions more of its citizens to visit Hong Kong amid growing concern that the city's infrastructure would be unable to cope.