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His own hopes of a pro boxing career ended at 23 when he was stabbed through the hand by a rival gang member.
But rather than carrying on down the wrong path he has helped others.
Now 41, he provides free classes to hundreds of young people at his Nottingham School of Boxing, with some even dreaming of reaching the Olympics.
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Bryer Wheatley, one of the young people Baz has helped, said: "When I was younger I used to be on the streets, carrying weapons, and I was involved in crime. I had no future. Baz has got me into college.
"He got me a part-time job and put me on the right track. I have even become a national junior boxing champion and have aspirations of going to the Olympics one day. If it weren't for Baz, my mum and dad would have thrown me out and I would have ended up in prison."
Baz received the trophy in Birmingham on Sunday at the annual BBC Sports Personality show after winning the East Midlands award earlier in the month.
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Regional awards organiser Natalie Jackson of BBC East Midlands Today said: "Marcellus's voluntary work totally bowled over the judging panel. Nottinghamshire Police and Crime Commissioner Paddy Tipping told us youngsters listen to Baz because they can relate to him.
"His work is a real life changer and the effect of it on breaking the cycle of crime is immeasurable, and the judges could see why."
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Boxing club founder Marcellus Baz has been named the BBC Get Inspired Unsung Hero award winner at the 2016 Sports Personality of the Year awards.