"They can lock up our bodies, but they cannot lock up our minds", Wong told reporters outside the High Court before the ruling was handed down.
Wong and 19 other demonstrators were found guilty of criminal contempt of court because they refused to obey a court injunction order to leave a protest zone in late November of that year.
Wong, 21, who became the face of the 2014 Umbrella Movement, was handed a three-month sentence on a contempt charge for obstructing clearance of a major protest encampment, to which he pleaded guilty. The party said that they "had no regrets in relation to civil disobedience, and only hope the public will understand that their actions that day were motivated by a desire to achieve universal suffrage and a fair, democratic society".
Wednesday's jailings are seen as part of a broad crackdown on protesters who joined the Umbrella Movement, and scores more could go to jail in coming weeks in what activists reckon is an attempt to smother the democracy movement.
"A few months' jail term has a limited impact on these secessionists, and the judge also can't prevent more youths from following these activists", he said. The pair were also denied bail, as Chan said the court did not have the jurisdiction to do so.
Raphael Wong Ho-ming, vice-chairman of the League of Social Democrats, was sentenced to four-and-a-half months in jail, while the other 14 received suspended sentences or fines.
Benedict Rogers, founder and chair of the United Kingdom -based rights group Hong Kong Watch, tells TIME he was "surprised and shocked" by the ruling, but that it will be unlikely to derail Wong and his peers in their pursuit of universal suffrage and democratic norms in Hong Kong.
They failed to win concessions and since then leading activists have been charged over their involvement.
He is already on bail pending an appeal over a six-month sentence for another protest-related offence.
Under the deal, citizens have the right to freedom of speech and a partially directly elected parliament, as well as an independent judiciary. The judge who heard their appeals on Tuesday will issue a ruling on a later date.