Radwanski suffered a heart attack Thursday in Toronto, his son Adam said in an interview.
"He was warm, funny and he definitely had a strong passion for life, and he was a fairly large personality both at home and outside of it," Radwanski's only child said Friday.
The son of Polish immigrants, Radwanski attended McGill University's law school but chose the life of a reporter over the courtroom. He began his career at the Montreal Gazette, mixing in hard news with cultural stories including John Lennon's famous 1969 bed-in at the Queen Elizabeth Hotel. He also worked for a time as a correspondent in the parliamentary press gallery in Ottawa.
Radwanski went on to work on the editorial pages of the Toronto Star, becoming editor-in-chief and winning back-to-back National Newspaper Awards in the early 1980s. In 1978, he published a bestselling biography of Prime Minister Pierre Trudeau.
Radwanski jumped into public affairs in the mid-1980s working on an influential study of Ontario's education system for then premier David Peterson. He helped write speeches and policy in the early 1990s for Liberal Leader Jean Chretien, who ultimately appointed Radwanski to the post of federal privacy commissioner in 2000.
Radwanski took to the job with zeal, and ruffled feathers with his early defence of online privacy and his scrutiny of public surveillance. He opposed traveller tracking proposals following the Sept. 11 terrorist attacks, saying at the time the Liberal government had "lost its moral compass."
"I think he saw a real need there and was not shy in doing it, and I think annoying the people who had appointed him," said son Adam, a columnist with the Globe and Mail.
"He definitely had a take-no prisoners approach to that job."
But it was Radwanski's spending rather than policy moves at the privacy commissioner's office that garnered him the most headlines, as he found himself at the centre of one of Ottawa's first major expense stories.
A 2003 auditor general's report into hefty hospitality expenses at the privacy commissioner's offices declared there had been an abuse of public funds. Radwanski resigned the post in the aftermath.
The matter was referred to the RCMP, and Radwanski was charged with fraud and breach of trust. A judge in 2009 acquitted the former commissioner, saying there was no evidence he did anything outside the rules or against the public good.
A decade later, the attitude to expenses in the capital has changed radically, and a series of senators are facing the same type of scrutiny and charges that Radwanski did.
Radwanski's career never recovered from the controversy despite the legal victory. He continued to be a close watcher of Canadian journalism, privacy issues and Canadian politics, posting to Twitter as recently as Friday.
"I think it was a nightmare for him being charged with anything, and being acquitted I think he thought, 'Now I've been exonerated and now I can re-engage in public life,' and he didn't really get a chance to do that," his son said.
Friend and Ottawa lawyer Michael Crystal described Radwanski as devoted to his son and passionate about Canada and privacy rights.
"I always thought to myself that it was quite unfair," Crystal said.
"Here was someone who had been exonerated, who had been a very good privacy commissioner, had been given the cold shoulder by political Ottawa, and was left to fend for himself with a black cloud over his head."
Note to readers: This is a corrected story. A previous story had incorrect dates for Radwanski's newspaper awards and appointment to privacy commissioner role