Mak Chi-shing, 27, an air conditioning technician, approached Bay in October and demanded HK$100,000 (US$12,900) on the first day of filming in the city's Quarry Bay district for "Transformers: Age of Extinction".
Mak claimed he had not been paid adequate compensation for the disruption caused by filming and tried to hit the Hollywood director with an air conditioning unit after he was refused further payment, according to Bay's own account.
"He is convicted of blackmail and assaulting a police officer in the execution of his duty, the sentence was 30 months imprisonment," a judiciary spokeswoman told AFP.
Judge Josiah Lam Wai-kuen said the case had tarnished Hong Kong's reputation abroad, the South China Morning Post reported, an aggravating factor in the sentencing.
Police arrested the two men shortly after the attack on the "Armageddon" director, who recounted details of the incident at the time in a statement on his website.