In the country's fourth election in seven years, the socialist New Democratic Party became the official opposition in a political revolt by the Liberals, who ended up losing 43 seats.
Liberal Party leader Michael Ignatieff ended up third in his Toronto-area district and, in a defiant concession speech, said it would be for his party to decide his future.
The separatist Bloc Quebecois also shrank its presence from 49 seats to just four in Monday's vote. Party leader Gilles Duceppe lost in his own Montreal-area riding, prompting him to announce his resignation as party leader Monday night.
Results Tuesday showed Conservatives took 167 of the 308-seat Parliament, followed by the NDP with 102. Liberals captured 34 seats, the Bloc Quebecois won four and the Green Party made its parliamentary debut with one seat in British Columbia.
Harper told a jubilant crowd Monday night in Calgary, Alberta, the resumption of government would begin "as early as tomorrow."
In Toronto, NDP leader Jack Layton told a raucous party gathering his leftist party wasn't necessarily going to battle every Conservative move.
"We'll support positive suggestions that we'll bring forward and support the government when it's making progress," Layton said.