Tariq Jahan, 46, was found guilty of inflicting grievous bodily harm following a four-day trial at Birmingham Crown Court.
Jurors heard that he punched 34-year-old Sajjid Ali after the pair got into an argument in Handsworth, Birmingham, on July 6 last year.
The attack happened a month before Jahan won national acclaim for an impassioned appeal for peace after his 21-year-old son Haroon was killed during disorder in the Winson Green area of Birmingham.
Judge William Davis QC said: "People who break people's jaws in this kind of mindless violence normally go to prison but I take a view that because of his extraordinary position it is right to suspend sentence."
Addressing Jahan, he added: "There is in your case this extraordinary combination of events. For that reason and that reason alone I can suspend the sentence."
The judge told Jahan: "Ordinarily this would mean that you would go to prison for 12 months but this all happened last July and in August, as everybody in this court knows, you suffered the loss of one of your sons, which was desperate in itself.
"But more particularly, in the aftermath of this loss you took steps which in my judgment... probably prevented really serious disorder continuing in Birmingham."
The judge, who said he had sentenced many people for riot-related crimes since last summer, described Jahan's actions as "a genuine public service
Jahan's sentence was suspended for two years and he was ordered to complete 100 hours of unpaid work.
He was also told to pay £1,000 compensation to Mr Ali within 12 months.
The court heard that Mr Ali was taken to hospital by his manager and treated for two fractures to his jaw after the altercation outside his workplace in Factory Road. He also lost two teeth and had bruises to the left temple area of his face.
He told the jury that Jahan had attacked him after accusing him of staring at his wife, who was in the car with the defendant before the incident.
Mr Ali said Jahan drove up to him in his car and said: "Oi, why you staring at me?" before getting out of the vehicle and accusing him of "staring at my missus".
The victim told the court Jahan grabbed him by the throat, knocked him to the floor and then punched him while he was on the ground.
Jahan, who pleaded not guilty, had admitted hitting Mr Ali in the face but told the court he acted in self defence after Mr Ali headbutted him.
He said he pulled over and got out of his car to speak to Mr Ali after the pair got into an argument over Jahan sounding his car horn at a van blocking his path. Mr Ali had been standing on the roadside speaking to the driver of the van, Jahan said.
He said he wound down the window on the passenger side of his white Mitsubishi car and asked Mr Ali about where he was from and what his religion was in an attempt to relate to him and find some common ground.
He said: "I asked, 'are you Pakistani, Iraqi, Sikh, Hindu or Muslim', just to try to relate to him. He looked very similar to me and I suspected he was of Asian descent and because he was a young man and he looked a bit upset I was trying to calm him down.
"I thought if I could relate to what he was, I could talk to him better.
"I normally speak to people who are aggressive."
Jahan said he was "upset" when the incident became violent, adding: "I didn't want confrontation, I just wanted to try to resolve something that I thought I could resolve. I wasn't proud of what I had done. I was not happy.
"To see what I had done played on my mind as I drove back home. To me, it was the only means of defending myself.
"I was hoping to calm him down. He was a young man and he seemed to be getting aggressive over a minute issue."
Asked why he did not just drive away, he said: "It is not in my nature to drive off. You try to resolve issues, you don't run away from issues.
"I thought if I talked to him I could calm him down. I suppose now with hindsight I could have, I should have, driven off. It probably wouldn't have got to this stage.
"If human beings can relate to one another, they tend to calm down."
The judge said he sentenced on the basis that Jahan delivered a single "hard punch" to Mr Ali.
He said: "It was of significant force to break his jaw when he was on the floor."
Jahan, who received a Pride of Britain special recognition award for his compassion and dignity in the aftermath of his son's death, made no comment as he left the court.