Kwok, who was then a lawmaker assistant, earlier pleaded guilty to contempt and resisting or obstructing a Legco officer.
The court heard that he had thrown down a stack of paper from the public gallery during a committee meeting. A security guard was also injured as he tried to subdue Kwok.
In sentencing, West Kowloon magistrate Minnie Wat said the 600 or so pieces of paper Kwok dropped could have hit people and this would have amounted to assault.
She said the meeting taking place was important, being as the House Committee had for months failed to elect a chairperson.
Kwok’s action had distracted people and caused further delay to a meeting that had already been repeatedly interrupted, wasting manpower and public money, the magistrate said.
She said the security guard might have fallen because he lost his balance, but Kwok still bears “unshirkable responsibility” for the injury the guard suffered.
Kwok was already serving an eight-month jail sentence, over a banned June 4 vigil last year.