In August, Wong, Nathan Law and Alex Chow were sentenced to between six and eight months in prison for public order offenses stemming from the protests, which shut down parts of the city for several months.
They were originally given community service and suspended sentences, but an appeals court controversially upgraded that
to prison time. Tuesday's decision quashes their prison sentences and reinstates the initial ruling.
While the Court of Final Appeal (CFA) endorsed a higher standard for public order offenses put forward by the Court of Appeal, it said the judges were wrong to apply that standard retroactively to Wong, Law and Chow's case.
However, the city's top court warned that in future, public order offenses, even those stemming from civil disobedience, would be dealt with strictly and could result in prison terms.
Nor is Tuesday's win the end for Wong. He's currently out on bail appealing a separate conviction, for contempt of court, also stemming from the 2014 protests.
"I would not say this is a win and there is no reason for us to celebrate. What we are up against is the court taking a very narrow definition of non-violent civil disobedience actions," said Wong.
"The road ahead is still very difficult."
Tuesday's case was one of dozens brought against protesters and pro-democracy politicians since the 2014 demonstrations, which analysts say
are designed to sap morale and dissuade other young people from taking to the streets.
In the past year or so, pro-democracy politicians have been disqualified from office
, had numerous court cases brought against them, and prospective candidates have been barred from standing in elections to the city's parliament.
Last month, Agnes Chow, a member of Wong and Law's political party, Demosisto, had her application to run in an upcoming by-election denied
on the grounds that the party's platform advocates for Hong Kongers to be allowed to decide on their own future, including voting on a potential break from China.
In 2016 several candidates advocating for Hong Kong independence were also barred from running for office
-- on the grounds that this is contrary to the city's constitutional principles as a Special Administrative Region of China.
In a statement
, a group of senior Hong Kong lawyers said the decision to bar Chow was "unreasonable, unlawful and unconstitutional."
"Disqualification of candidates with certain political opinion or affiliation frustrates the core purpose of an open and fair election, which is to guarantee the free expression of the will of the electors," the statement said.
The move was also widely denounced by international observers. A European Union spokeswoman said
it "risks diminishing Hong Kong's international reputation as a free and open society" and was in contravention of the International Covenant on Civil and Political Rights, to which Hong Kong is a signatory.
Speaking to reporters
following the decision however, Hong Kong Chief Executive Carrie Lam said "any suggestion of Hong Kong independence or democratic self-determination ... deviates from the important basic principle of 'one country, two systems'," under which the city is governed.
Lam had denounced international criticism
of the Chow decision as interference in Hong Kong's internal affairs, a point she returned to this month after several US lawmakers nominated Wong, Law and Chow for this year's Nobel Peace Prize
"This nomination could not be more timely as Hong Kong's long-cherished autonomy continues to erode, and Umbrella Movement leaders face reprisals simply for espousing basic human rights and freedoms," said Senator Marco Rubio in statement. "Joshua Wong and his fellow pro-democracy advocates have been unflinching in their peaceful and principled commitment to a free and prosperous Hong Kong."
The statement referenced the death last year of jailed Chinese dissident Liu Xiaobo
, the first Nobel Peace Prize laureate to die in state custody since Carl von Ossietzky in Nazi Germany in 1938.
In a joint statement, the three said they were honored to receive the nomination, adding "at this critical juncture, we need to join hands with the international community and together defend Hong Kong as a bridgehead for democratic movements."
Lam however said the move
was "regrettable" and accused the US lawmakers of seeking "political intervention" in Hong Kong's affairs.
In a statement
, China's Ministry of Foreign Affairs said "Hong Kong's affairs are China's domestic affairs, and China firmly objects to anyone intervening through any means."
Only politicians, former laureates, and certain civil society groups can nominate
people or institutions for the Nobel Peace Prize.
While the award has been widely criticized in the past from multiple political quarters, it still carries huge international cache.
China was so incensed with Liu's win that it cut trade with Norway
, hurting the country's economy, and similar reaction could be expected were Wong, Law and Chow to win.