Bainimarama, who led Fiji for 16 years, faced the country's High Court in the capital Suva on Thursday.
The conviction relates to Bainimarama's role in influencing a police investigation into funding of the region's biggest university, the University of the South Pacific, in 2019.
The courtroom went silent after the sentence was read out, with Bainimarama later being led out in handcuffs, surrounded by police, and into a waiting police van.
He did not react after the sentence was read out, but his wife, who was sitting by his side, broke down in tears.