Wong Chi-wing, 60, was found guilty after a retrial last week for taking part in the violence nearly six years ago on July 21.
Wong’s lawyer argued in mitigation last week that his client had a rather small part in the clashes.
But District Court judge Eddie Yip dismissed the plea.
Yip said the case was very serious.
Wong, he said, was among a group of white-shirted men that carried out what he described as “an indiscriminate attack” on others inside and near Yuen Long MTR station.
The sentencing starting point for two co-defendants in the case was seven years behind bars, Yip noted, and the same was applied to Wong with no discount offered.
Wong had been acquitted in 2021, and a higher court ordered a retrial after the Department of Justice won an appeal.
Yip convicted Wong last week based on his clothing and video footage from the scene of the clashes, with the judge saying he had not made out Wong in the footage in the initial trial.