Greg Brotherston, 31, pleaded guilty to manslaughter last month, admitting he punched Richard Green, 57, outside the Country Rose Pub in Colwood on Oct. 8.
Green, who was intervening in an argument between Brotherston and a former girlfriend, fell and hit his head on the pavement. He died in hospital two days later.
After sentencing, Green's son Kevin said he was pleased Brotherston would have to do time in a federal prison.
On Tuesday, Brotherston’s sentencing hearing ended with a tearful apology to the victim's friends and family.
"I could never imagine this happening,” he told the courtroom. “I'm so stricken and I'm so sorry for this."
Brotherston's lawyer argued his client could not have predicted Green’s death, arguing he should only spend one to two years in jail.
The Crown had asked for four to six years, citing Brotherston's record of violent offenses and the senselessness of the crime.
Brotherston, along with his father, Ken, and his brother, Ken Junior, were acquitted of murder in the death of a drug dealer in 2010.
Ken Brotherston and Marie Brotherston were at one time municipal councillors in the Victoria suburb of Highlands.