In a forthright interview on Sunday, Ignatieff, who led the party to one of its worst electoral defeats in history during the 2011 campaign, told CTV's Question Period that Trudeau possesses political skills he didn't have.
The challenge, he said, will be for the new Liberal leader to convince Canadians that he can be a good prime minister.
"I've got a lot of respect for his political shrewdness," said Ignatieff, who is promoting a new book Fire and Ashes about his time in politics.
He shied away from giving Trudeau direct advice, but suggested the Liberals miscalculated by trying to demonize Prime Minister Stephen Harper and paint him as a "right-wing Republican" zealot.
The reason Harper remains in power is because he appeals to the "centre right" of Canadian politics, said Ignatieff.
After losing his own seat in the 2011 election, the former Harvard professor returned to teaching, but this time in Toronto.
He said he carries no grudges but conceded in the CTV interview that was he was hurt by the Conservative attack ads that painted him as a political interloper who was "just visiting."
The fodder for the ads was Ignatieff's 34 years spent outside of the country as an academic, journalist and commentator.
He said he feels the attacks disparaged those who learn something about the world and travel abroad.
"Most young Canadians I talk to are going to spend most of their lives out of the country," he said. "We're one of the most global countries in the world, so the concern I have is that what (Harper) got away with me, he mustn't get away with the next generations. I want young Canadians to spend 10 years overseas, putting their talents to use somewhere else and then coming back to serve their country."
In a separate interview Sunday on The West Block with Tom Clark, Ignatieff said he doesn't regret his time in politics despite the bruising.
“I’m glad I did it,” he said. "I'd probably do it all the same, actually.
“It was an extraordinary experience to put my skates on and I’m not going to complain because I took a few checks into the boards and got slapped down a bit. If you decide to do that, you have to take everything that comes at you. The stupidest thing to do is complain about it.”
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