Heart Surgeon's One Punch Killer Jailed For 10 Years

A man who killed a respected Melbourne heart surgeon with a single punch will serve at least a decade behind bars after becoming the first person sentenced under the Victoria's 'coward punch' laws.

Patrick Pritzwald-Stegmann, 41, suffered fatal head injuries when punched by Joseph Esmaili at Box Hill Hospital in May 2017.

His killer, now 24, was found guilty of manslaughter last year and was on Wednesday ordered to spend up to 10 years and six months in prison.

He's the first person to receive a mandatory minimum decade-long prison term under Victoria's 'coward punch' laws, meaning he must serve at least 10 years before becoming eligible for release on parole.

Pritzwald-Stegmann was leaving the hospital when he stopped to tell a group -- including Esmaili -- to stop smoking near the entrance.

An argument broke out between the pair.

Joseph Esmaili. Image: AAP

"Unfortunately neither of you was prepared to simply walk away from the argument," Justice Hollingworth said.

Esmaili punched the surgeon with such force he was knocked unconscious and suffered "catastrophic" injuries when his head hit the floor.

His family switched off his life support a month later.

Patrick Pritzwald-Stegmann. Image: AAP

Justice Hollingworth said his death had turned the lives of his family, including his wife and young twin daughters, upside down.

Esmaili had expressed some remorse for his actions that day, but still blamed Pritzwald-Stegmann for what had occurred, evidenced by his repeated claimed he had acted in self-defence.

"You still have some way to go before you genuinely accept responsibility for your actions that day," the judge told him.