Barrie police Const. Jason Nevill was convicted in June of assault causing bodily harm, attempting to obstruct justice and fabricating evidence.
Nevill initially maintained that Jason Stern was intoxicated and had attacked him with intent to resist arrest at a mall in November 2010.
However, charges against Stern were dropped after video surveillance emerged showing the officer attacking him without provocation, and beating him even after handcuffing him, leaving a pool of blood.
In addition to the year in jail, Ontario court Judge Lorne Chester also sentenced Nevill to one year on probation.
Barrie police Chief Kimberley Greenwood says Nevill is suspended without pay and his future with the force will be decided at a Police Services Act hearing.
A disciplinary hearing has commenced on allegations of unnecessary use of authority, deceit, and discreditable conduct, Greenwood said.
"I expect our officers to be held to a higher standard of behaviour," Greenwood said Thursday in a statement.
"If there is involvement of any of our officers in a criminal act, or any other act that violates our sworn oath of office we are all accountable for our actions," she said.
Greenwood called Nevill's conduct "unacceptable," and a betrayal of her police force's sworn oath and principles.
"I am disappointed that Const. Nevill's actions have tainted the image of the Barrie Police Service and the committed members within."
The incident occurred after Stern's friend broke a Christmas ornament.
In convicting Nevill, Chester called the officer's use of force "excessive" from the outset, noting that Stern was "rag-dolled" by the burly constable.
Stern is suing Nevill and the mall for $1 million, arguing he sustained permanent physical and emotional injuries from the beating.
When he took the injured Stern to hospital, Nevill poked fun at the victim for the amount of blood that was on the back of his cruiser, according to Stern's lawyer, Bernard Keating.
After Nevill's conviction in June, Greenwood said she'd spoken to Stern and apologized on behalf of the Barrie police.