The controversial MP intends to run for city council in a ward which overlaps much of the Scarborough-Agincourt riding he's represented since 1988.
Karygiannis said his decision was prompted by a desire to spend more time with his wife, five grown daughters and elderly mother, while continuing to defend the interests of his constituents.
However, the 58-year-old may also have concluded that his talent for bare-knuckle organizing — employed by both Jean Chretien and Paul Martin to secure the party's leadership — was unlikely to be valued by Justin Trudeau.
The new leader has declared he won't tolerate the kind of nasty infighting and ruthless machinations that he believes contributed to the decline of the once-mighty Liberals into a third-party rump.
Trudeau's team sought to send a strong signal on that front last month, barring Christine Innes from running for the Liberal nomination in Toronto's Trinity-Spadina after receiving complaints about alleged bullying and intimidation tactics by her husband, former MP Tony Ianno.
Karygiannis, who referred to himself Tuesday as "the last samurai in our party," has faced similar complaints over the years about his own hardball style of politics.
However, he denied that had anything to do with his decision to resign.
"Justin and I get along famously," he said in an interview Tuesday, shortly before informing the House of Commons of his immediate resignation.
Rather, Karygiannis said it was a snowstorm in February, while he was driving back to Ottawa from Toronto, that got him thinking about how much longer he wanted to make the weekly commute.
"I started on a Sunday night, around 8 o'clock, and I didn't get there until about 3 (a.m.). And I said, what am I doing?" he recalled, worrying that one day he might "hit the ditch."
Karygiannis, whose father died last year, said he wants to be able to spend time with his 84-year-old mother every day and to "sleep in my bed next to my wife" every night.
At the same time, he said he still has a "passion for politics." Since the current councillor for his ward, Mike Del Grande, has decided not to seek re-election, running to succeed him seemed an ideal way to indulge that passion closer to home.
Trudeau announced last week that Karygiannis would no longer be the party's veterans affairs critic. However, he had nothing but kind words after the MP tearfully announced his resignation.
"This member has always made his constituency his priority," Trudeau told the Commons. "There is no better reflection of his dedication to his constituents than the fact that they have elected him to this chamber in eight straight elections."
Trudeau praised Karygiannis for his contributions to relief efforts in the wake of disasters around the globe, his passion and his tendency to never mince words.
Overcome with emotion, Karygiannis enveloped Trudeau in a bear hug at the conclusion of his remarks.
New Democrat MP Niki Ashton praised Karygiannis' "tremendous work" on behalf of immigrant diasporas, particularly Greek-Canadians. Defence Minister Rob Nicholson, who was an MP when Karygiannis was first elected, commended him for his "determination and enthusiasm" in promoting human rights.
Among his accomplishments, Karygiannis counts persuading Parliament to recognize the 1915 genocide of Armenians in what is now Turkey as a crime against humanity.
In his final speech in the Commons, Karygiannis also referred proudly to his skill as a political organizer, although his aggressive tactics — particularly among multicultural communities — often landed him in hot water.
He quoted a letter from Martin last year, in which the former prime minister said Karygiannis "can out-campaign and out-organize just about anyone."
"There are very few people that have the capability to organize and help others get elected," Karygiannis said of himself. "Many people say I'm the last samurai in our party."
He was banned by the Ontario wing of the party from attending delegate selection meetings during the 1990 leadership contest, after he was accused of physically accosting a Martin supporter.
Karygiannis, who was organizing for Chretien at the time, was also famously accused of putting chewing gum in the coin slots of pay phones to prevent Martin organizers from calling supporters who'd been suspiciously misinformed about the timing of a delegate meeting.
However, Karygiannis eventually became one of Chretien's severest critics and an organizer for the Martin camp during the 2003 leadership contest.
In 2006, he was national co-ordinator for Joe Volpe's ill-fated leadership campaign. He quit mid-campaign over a difference of opinion over Israel and wound up calling the police to stop Volpe from removing computers from his campaign headquarters, which had been leased in Karygiannis' name.
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