The 20-year-old had been on bail since a jury convicted him of grievous bodily harm in February.
Williams had argued self-defence after admitting to punching Matthew Robertson, then 29, outside a nightclub in his home town of Albany in December 2012.
Robertson suffered a broken jaw in the attack, for which the maximum penalty is 10 years in jail, but Williams was given a 12-month sentence, suspended for 12 months.
Williams issued a statement via the club on Tuesday afternoon expressing his relief at the verdict.
“I would like to apologise to all of those hurt, one way or another, by my actions," he said.
"I’m deeply sorry for the pain I’ve caused a lot of people. The last 16 months have not been easy for anyone involved.
“I want to thank my family, friends and football club for their support throughout an extremely trying time. I look forward to quietly getting on with my life with a new understanding of the harm one bad decision can cause.
“I have certainly learned that, regardless of the circumstances, you have to be strong enough to walk away. To be the better man.
“I’m relieved and grateful for the opportunity to return to football, a game I value and respect in a new way after what I have put myself and others through.”
He has appeared in 22 games for Collingwood since making his debut in 2012.
Williams was supported in court by Pert, Eade and the club's welfare manager.
The Pies ordered Williams to undertake volunteer work with the Salvation Army in the aftermath of the incident.
"He's already put a lot of work in place, working with the Salvation Army, working on himself, and we don't expect - and even the courts said that - we would see any similar incidents like this," Pert said.
The judge issued Williams with a lifetime restraining order preventing him from contact directly or indirectly with his victim.
He’s not allowed to go within 50 metres of Robertson’s residence or workplace.
The prosecution has 21 days to decide if it wishes to appeal against the sentence.
It is not known whether Robertson intends to undertake any civil action.