Following an election upset that saw the Conservatives relegated to Official Opposition after nearly a decade in government, and the resignation of Stephen Harper as party leader, the question looms: Who will lead the party next?

Taking the stage in Calgary Monday night, Harper said the election results were "certainly not" what the party had hoped for, but, he added, "the people are never wrong."

The Liberal Party captured a decisive victory Canada's 42nd general election, taking 184 of parliament's 338 seats as of Tuesday morning. The Conservatives took 99 seats, the NDP won 44, the Bloc Quebecios took 10 and the Green Party held onto one seat.

"The disappointment you feel is my responsibility and mine alone," Harper said, suggesting that he has no regrets about how the campaign was fought.

"We put everything on the table, we gave everything we have to give, and we have no regrets whatsoever," he said.

Despite his party’s losses, including a complete shut-out in Atlantic Canada and the loss a several seats in the vote-rich Toronto-area, the Conservative leader handily won his Calgary Heritage riding, taking 63.8 per cent of the vote.

Conservative Party President John Walsh said in a statement Tuesday morning that Harper plans to stay on as a Member of Parliament.

“The Prime Minister indicated that he will continue to sit as a Member of Parliament and asks that a process to both select an interim leader and initiate the leadership selection process in our party begin immediately,” Walsh said.

Walsh released a similar statement ahead of Harper’s late-night concession speech, noting that the party had been instructed to begin the process of choosing an interim leader, and to start the leadership selection process.

When Harper took the stage, however, Harper made no mention of plans to resign as Conservative leader.

"When the next time comes, this party will offer Canadians a strong and clear alternative, based on our conservative values," he said.

Harper biographer and Maclean's columnist Paul Wells said the Conservative leader made a point of not publicly announcing his resignation.

"He did not want you to use that clip on TV this morning," Wells told CTV's Canada AM on Tuesday. "To the end, he tightly controls his media message."

Wells said Harper's departure as leader is "devastating" for the party, and noted that there's no clear candidate to replace him.

"There are impressive people, but there's no one who just obviously looks like the kind of person who can take on a majority Liberal prime minister."

Who are the contenders?

Jason Kenney

The Calgary MP who served as minister of national defence and minister of multiculturalism under Harper, cruised to his sixth-straight election victory on Monday night.

Kenney is credited with making inroads into Canada's ethnically diverse ridings and is considered a favourite to replace Harper.

Kenney told CTV News Monday night, that it was "very unfortunate" the party was wiped out of Atlantic Canada.

"When all of this is done we're going to have to take a look and see why exactly we got this kind of result," he said.

But Kenney avoided addressing a possible leadership run.

"All those questions will be for another day," he said.

CTV's Power Play Host Don Martin said he's heard from "good sources" that Kenney is planning a leadership run.

"It would be a cakewalk for him to be brutally honest," Martin said. "There's no one else who's really in serious contention."

Brad Wall

Saskatchewan Premier Brad Wall is also considered a possible contender for the Conservative leadership.

Wall was asked Monday night if rumours that he's learning French have anything to do with a possible run for the Tories top job.

The popular premier responded: "Ce n'est pas vrais… I’m not taking French lessons. I have the job I want."

Peter MacKay

The former justice minister announced in May that he decided not to seek re-election after nearly 20 years in federal politics. At the time, MacKay said he planned to turn his attention to his "young and growing family."

On election night, the Nova Scotia native said the results are "not at all what we hoped for."

Asked if he's considering a run for the leadership of the Conservative Party, MacKay said "that's not on the table."

"I didn't step back from politics with the desire to jump back in," he told CTV News Monday night. "But politics is something I grew up with, I grew up around and I will always watch very closely, follow what's happening and I'll always be a conservative. There's no question about that."

Lisa Raitt

The Harper government's transportation minister was re-elected in the Milton, Ont., riding she's held since 2008.

Raitt has held strong cabinet posts over the past seven years and is considered a strong communicator who is very well-liked among her colleagues.

"The new Conservative caucus will be very happy that (Raitt) was elected," CTV's Ottawa Bureau Chief Robert Fife said Monday. "She is a potential leader of the party. She is a very hard working person (and) she's enormously well-liked by all sides of the House of Commons."

Other possibilities:

Tony Clement: since he was elected in the Parry-Sound-Muskoka riding in 2006, Clement has served in a number of Conservative cabinet roles, including President of the Treasury Board.

Doug Ford: The controversial former Toronto councillor has said he'd consider taking over for Stephen Harper if the opportunity arose. Doug Ford and his brother, infamous former Toronto Mayor Rob Ford , well-known conservative supporters and drew a large crowd at a Harper rally they attended towards the end of the campaign.

Kellie Leitch: Leitch, an orthopedic pediatric surgeon, won back her seat in the Ontario riding of Simcoe-Grey. She was first elected in 2011, and served as the Minister of Labour and Minister for the Status of Women.