Le Minh The, 56, was indicted for "abusing democratic freedoms to infringe upon the interests of the State, the legitimate rights and interests of organizations and/or citizens."
Prosecutors said between March and August last year he broadcast seven live videos on Facebook that showed his extremist attitude and libeled the party and the government.
He called on people to protest and riot to overthrow the government, they said.
The pleaded guilty to all the charges.
The judges said his behavior had been intentional, professional and well-prepared and severely endangered security and social safety.
Under Vietnam's Penal Code, "abusing democratic freedoms to infringe upon the interests of the State, the legitimate rights and interests of organizations and/or citizens" is a crime punishable by up to seven years in prison.
On Monday, a HCMC appeals court upheld jail terms of between eight and 15 years for five people found guilty of trying to "overthrow the people’s administration."