Prominent Calgary lawyer Hersh Wolch — a passionate, tenacious defender of the wrongfully convicted — has died of a heart attack at the age of 77.

The Calgary law office where Wolch worked with his son Gavin confirmed his death Monday morning. 

"He was the consummate defence lawyer," said Greg Rodin, who worked with Wolch for nearly 40 years. "He was dogged in his pursuit of justice for his clients."

Wolch helped free David Milgaard, the Saskatchewan man who spent 23 years in prison for a murder he did not commit.

DNA evidence eventually cleared Milgaard in 1997 and helped convict another man, Larry Fisher.

Wolch was also a member of the legal team that helped clear Steven Truscott, charged with rape and murder, and Kyle Unger, who spent 14 years in prison for murder. 

Wolch was responsible not only for a number of cases that set legal precedents, he also helped expand Canadians' constitutional rights, said Rodin who had most recently worked with his mentor on both the Milgaard and Unger cases.

"He has been a shining example of a person who contributed immensely to the development of Canadian criminal law."

On social media, condolences and tributes began pouring in Monday as members of the legal profession learned of Wolch's death.

Rodin says Wolch had earned the respect of the bar, the judiciary, clients and colleagues.

"His legacy is that he has raised the bar for many lawyers in terms of how they practice law and that can only enhance the justice system."

In 2015, he received a distinguished service award from the Law Society of Alberta and Canadian Bar Association. The award credited him as being "instrumental in advocating for, and helping to develop many of the principles that now form part of the Canadian Charter of Rights and Freedoms and our justice system in general."

Wolch was born in Winnipeg and rose to prominence in the mid-1990s when he took on Milgaard's case. He was called to the Bar of Manitoba in 1965, Saskatchewan in 1972 and Alberta in 1978.

Along with several children, Wolch also leaves behind his wife, Alberta Court of Appeal Justice Sheilah Martin.

Rodin says Wolch is not just a colleague but a beloved friend and mentor.

"He was a wonderful guy, he had a great sense of humour. He was a joy to be with."

With files from The Canadian Press