Canadian criminal defence lawyer Edward Greenspan, whose high-profile clientele and impact on helping form the legal system made him renowned internationally, has died at age 70.

Greenspan's law firm in Toronto, Greenspan Partners LLP, on Wednesday morning confirmed that he died in Phoenix, Ariz., surrounded by his family. The cause of death has yet to be released.

'I will never be tired and I will never be weary. I am as enthusiastic about the law today as I've always been.' - Edward Greenspan in 2009 profile

Edward Leonard Greenspan was born in 1944 in Niagara Falls, Ont., and would have turned 71 in February. He attended the University of Toronto and Osgoode Hall Law School, and served as a defence lawyer for more than four decades. 

His lengthy list of famous clients included Conrad Black, Garth Drabinsky, Robert Latimer, Karlheinz Schreiber and members of the NBA's Milwaukee Bucks.

Greenspan gained national exposure as host of CBC's radio series The Scales of Justice in the 1980s and the TV series in the 1990s. He won a Gemini Award in 1993.

Greenspan played a large role in educating Canadians about the death penalty and was a vocal advocate against it.

When Canada considered restoring capital punishment in 1986 and 1987, about a decade after it was abolished, he toured the country to speak out against it, at a time when public opinion leaned heavily in favour of it. 

A free vote in the House of Commons, under the Mulroney government, was held in 1987 but it was voted down.  

As he did many times in his legal career, Greenspan prevailed.

"It's over now," he said at the time. "If it couldn't be returned with the largest Conservative majority in history, it won't ever be."

Clients were often controversial

Greenspan would later go on to defend major figures in Canada.

They included Robert Latimer, a Saskatchewan farmer charged with first-degree murder in what he said was the mercy killing of his disabled daughter Tracy. The case drew national attention and sparked fierce debate over euthanasia and the rights of individuals with disabilities.

'He was a brilliant lawyer who understood how important it is that everyone have a defence, and he was a tireless champion for human rights.' - John Tory, Toronto mayor

Latimer was convicted of second-degree murder by a jury, a verdict that was later upheld on appeal. But Greenspan had public opinion in his favour, as most Canadians surveyed at the time felt compassion for Latimer.

Greenspan's more controversial clients included media moguls Drabinsky, a Toronto theatre impresario, and Montreal-born businessman Black. Both were eventually convicted of fraud-related charges.

Edward Greenspan

Edward Greenspan represented clients such as Karlheinz Schreiber, Conrad Black and Garth Drabinsky in his storied law career. (Darren Calabrese/Canadian Press)

Greenspan's unsuccessful defence of media baron Black in 2007 resulted in a war of words in the media between the legal genius and his former client.

During his later years, Greenspan bristled at the notion he was slowing down, telling the Globe and Mail he was a workaholic.

"I will never be tired and I will never be weary. I am as enthusiastic about the law today as I've always been," said Greenspan in a 2009 profile. "Tired and weary? That really pisses me off."

Paying tribute

Greenspan was well respected in his field, as evidenced by the number of lawyers who have paid their respects as news of his death broke.

Toronto Mayor John Tory, also a lawyer, acknowledged Greenspan was "larger than life in legal circles."

"He was a brilliant lawyer who understood how important it is that everyone have a defence, and he was a tireless champion for human rights," said Tory. "On top of that he was a great citizen and a wonderful human being. 

"On my own behalf, and on behalf of the people of Toronto, I offer my sincere condolences to his family. He will truly be missed."

Greenspan's career "can only be described as exceptional," said Supreme Court Justice Michael Moldaver, a former Ontario judge and defence attorney, in a statement. 

"He stood out because the law was more than a business to him; it formed part of his very being," Moldaver said. 

Prime Minister Stephen Harper also issued a statement, simply saying, "Our thoughts and prayers are with his family."

Harper and Greenspan had been at odds over criminal justice legislation in recent years.

The funeral for Greenspan will be held Sunday at Beth Torah Synagogue — the time has not yet been confirmed.

He is survived by his daughters Samantha and Juliana, who is a law partner in his firm, and his wife Suzy. His younger brother Brian is also a prominent defence lawyer, and his sister Rosann Greenspan works as the executive director of the Center for the Study of Law and Society, University of California Berkeley.