His death was announced in a statement from the Les Twentyman Foundation on Saturday.
"Les inspired us all with his lifelong dedication to helping those in need and his profound contribution to our community has positively changed the lives of thousands of young Victorians and their families," it read.
"Our thoughts, love and prayers are with Les's wife Cherie and his family at this most difficult time."
Mr Twentyman received an Order of Australia medal in 1994 for his service to youth as an outreach worker.
The Les Twentyman Foundation worked to engage young people with their education, families and community.
Vale Les Twentyman, one of Melbourne's big characters. We were in contact just this week and he worked right up til the last. Thoughts and prayers to his family, friends, colleagues and all the people he helped along his road less travelled. — Bill Shorten (@billshortenmp) pic.twitter.com/lUWigXBeN5March 30, 2024
"In life Les was never afraid to say what was needed to be said, he gave a voice to the voiceless and leaves a legacy of helping the disadvantaged and those in need that will live long past his extraordinary life," the foundation said.
Born the eldest of five children to fruit shop owners in 1948, Mr Twentyman was raised in Melbourne's western suburb of Braybrook.
He was a candidate for Victorian parliament's upper house in 1992 and 1996 and in the lower house at the Kororoit by-election in 2008.
Federal Government Services Minister Bill Shorten said Mr Twentyman was "one of Melbourne's big characters".
"We were in contact just this week and he worked right up til the last," Mr Shorten said on social media.
Victorian Premier Jacinta Allan remembered Mr Twentyman as a devoted servant to people in need, and a "true son of the west" who uplifted and protected the disadvantaged communities he called home.
"He propelled progress, always demanding more and better," Ms Allan said.
"Les' legacy is the thousands of kids who can succeed because he spoke up, and generations of Victorians who can give back because he never gave up."
State opposition leader John Pesutto said Victoria was a better place for Mr Twentyman's lifelong work and passion.
"A fierce advocate on social justice issues, thousands of young and at-risk Victorians had their lives changed for the better due to the tireless efforts of Les and the foundation he established," Mr Pesutto said.
It is with great sadness that the Les Twentyman Foundation announces the passing of Les Twentyman. 🕊�— Les Twentyman Foundation (@LT_Foundation) Les passed away overnight at home, and we are all devastated with his loss. He will be greatly missed by all who loved and knew him. Vale Les Twentyman. 🧡 pic.twitter.com/6cvv7WKEuWMarch 30, 2024
Federal Assistant Minister to the Prime Minister Patrick Gorman said while it was a sad day, it was also time to reflect on Mr Twentyman's mission to lend a helping hand, reach out to people who needed support and find ways of showing compassion through action.
"We can all take that message away as we reflect on his life and his contribution, and maybe take a little bit more of Les Twentyman's contribution into our own lives and our own actions," Mr Gorman told reporters in Perth on Saturday.
The Western Bulldogs AFL club remembered Mr Twentyman, who served on its committee, as a dedicated teacher and youth worker whose love for football and the club was "fierce and enduring".
"The 2016 men's premiership meant an enormous amount to Les and in the days afterwards he wrote movingly about what a profound impact the win would have on the western suburbs and its people," the Bulldogs said in a statement.
