Trudeau called the snap election last month, hoping to parlay a smooth Covid-19 vaccine rollout -- among the best in the world -- into a new mandate to steer the nation's pandemic exit and pass his agenda without opposition support.
But after a bumpy five weeks of campaigning, his voice was raspy and he appeared set for a repeat of the close 2019 general election that resulted in the one-time golden boy of Canadian politics clinging to power yet weakened after losing his majority in parliament.
"You (Canadians) are sending us back to work with a clear mandate to get through this pandemic into brighter days ahead," Trudeau said, flanked by his wife Sophie Gregoire and their children on stage at a victory gala.
"That's exactly what we are ready to do," he said.
At 49, Trudeau had faced tougher political bouts and still came out unscathed.
After six years in power, however, his administration is showing signs of fatigue, and it was an uphill battle for him to convince Canadians to stick with his Liberals after falling short of high expectations set in his 2015 landslide win.
Trudeau 'lied to us'
Throughout the day, long lineups outside polling stations were observed by journalists in several major cities.
Douglas O'Hara, 73, casting a ballot in Trudeau's Montreal electoral district of Papineau, said earlier that he was "very disappointed" with the prime minister.
Although he believes Trudeau "did a half-decent job" managing the pandemic, he recalled that the leader had pledged not to go to the polls until the outbreak had subsided.
"Then as soon as he gets a chance (when) he thinks he's going to get a majority, he calls an election," O'Hara said. "I really believe he lied to us."
In Ottawa, Kai Anderson, 25, said Canada's pandemic response was her "number one" issue. "I think the prime minister did a good job managing the pandemic," she said.
Liz Maier, 72, of Vancouver said she too hoped for a Trudeau win for "consistency in leadership" during the public health crisis.
Entering the final stretch of the contest, Liberals and Conservatives -- the two main political parties that have ruled Canada since its 1867 confederation -- were virtually tied, with about 31 percent support each in public opinion polls, and four smaller factions nipping at their heels.