Justin Trudeau, 40, a charismatic member of Parliament since 2008, made the announcement in front of hundreds of supporters packing a community center in his Montreal district, ending days of speculation and adding sizzle to the political contest which officially begins next month and ends in April 2013.
Many Liberals hoped Trudeau would run for the leadership of a party that ruled Canada for much of the last century but was regulated to third-party status in the last election.
"I am in love with Canada. I want to dedicate my life to serve it," Trudeau said in French.
Pierre Trudeau, who died at age 80 in 2000, was prime minister for almost all of a 16-year stretch from 1968-84. Sweeping to power on a wave of support nicknamed "Trudeaumania," Trudeau had a charisma reminiscent of another young, dashing politician who had captivated the U.S. eight years earlier—former President John F. Kennedy. Trudeau's sophisticated, sometimes irreverent style fascinated and captivated his country.
Justin Trudeau was born while his father was prime minister, on Christmas Day, 1971.
Justin gave a moving eulogy at his father's state funeral which fed early speculation he would one day seek office, years before he eventually joined the ranks of his father's party.
He said Tuesday he's determined to breathe new life into a party he says has lost touch with middle-class Canadians. He said Canadian families have seen their incomes stagnant, their costs go up and their debts explode. He said the opposition New Democrats have stoked regional resentment and blamed the successful while the ruling Conservatives have chosen to favor western Canada's oil sector and promised that wealth will trickle down eventually.
"Both are tidy ideological answers to complex and difficult questions. The only thing they have in common is that they are both, equally, wrong," Trudeau said.
He said solutions can come from both the right and left and said he will create policies based on facts.
Analysts say Trudeau will have to make it clear his candidacy is more than just about his youthful charm and familiar name.
Trudeau is a big draw at Liberal fundraisers and polls have shown the former teacher to be a party favorite reaching rock-star like status.
Some observers fear Trudeau's leadership bid packs such punch it may turn into a coronation of the party's next leader, scaring away potential contenders. But critics have called him a political lightweight, saying little about major policy issues in his roles overseeing youth, amateur sport and immigration.
"The impression this leaves an outside observer is if he wasn't called Trudeau, no one would be talking about any political ambition," University of Montreal political scientist Pierre Martin said. "We have someone here with a thin CV."
His name and recognition will put him in the spotlight but as a whole he has yet to articulate a clear vision in public, Martin said
Trudeau only jumped into politics four years ago, but turned down offers to represent a usually safe riding to take on a stronghold of the separatist Bloc Quebecois, which he won. He increased his margin of victory in last year's election. But the Liberal Party fared poorly in the 2011 election, finishing in third for the first time in Canadian history and seeing the latest in a succession of party leaders fail to inspire electors amid non-stop attack TV ads by the ruling Conservatives.
It remains to be seen what kind of attack ads the Conservatives will run against a popular Trudeau should he become Liberal leader.
Former colleagues of current Conservative Prime Minister Stephen Harper say his long-term goals are to shatter the image of the Liberals—the party of former Prime Ministers Trudeau, Jean Chretien and Lester Pearson—as the natural party of government in Canada, and to redefine what it means to be Canadian.
Associated Press writer Rob Gillies in Toronto contributed to this report