Gabriel Nadeau-Dubois, who was at the forefront of the protests against tuition fees last spring, asked for help on Friday to contest a contempt of court ruling.
Two days, later more than 1,700 people had contributed to the legal fund.
Nadeau-Dubois said in a statement Sunday he's thankful for the assistance but he'll need a lot more money to launch a proper defence.
"I am both surprised and deeply moved by this expression of solidarity," he said.
"I thank those who have supported me, but we still have much work to do."
A judge ruled last week that Nadeau-Dubois encouraged students to ignore a Quebec City court injunction while he was doing a television interview in May.
His lawyer pleaded ignorance and argued there was no evidence Nadeau-Dubois was aware of the injunction, but a Quebec Superior Court justice rejected the argument.
Supporters have argued the ruling sets a dangerous precedent, limiting the free speech of leaders of social movements.