Nearly a year after his federal election defeat, former prime minister Stephen Harper finally resigned his House of Commons seat Friday, ending a career in politics that spanned more than two decades.

The former Conservative leader announced he was stepping down as MP for the riding of Calgary Heritage in a statement and video that was posted to his social media channels.

"On seven occasions, I have been deeply humbled by your trust and support, time and again. And I leave elected office proud of what our team accomplished together," Harper says in the video.

Interim Conservative leader Rona Ambrose offered her thanks and best wishes, saying he has a proud record in office.

She cited his foreign policy, including support for Israel and opposition to Russia's Vladimir Putin. On the domestic front, Ambrose said, he steered the country through the 2008 great recession.

"At the heart of that record was a recognition of the everyday challenges facing hardworking families. We proudly note that it was thanks to his principled guidance that Canadians enjoyed the lowest tax burden in 50 years — including a lower GST, income splitting for couples and tax free savings accounts," Ambrose wrote in a statement.

Prime Minister Justin Trudeau also acknowledged Harper's announcement and thanked his predecessor for his service.

"On behalf of Canadians, I thank Stephen Harper for his long & dedicated service to our country. My best wishes to you and your family today," Trudeau tweeted.

Harper stepped down as Conservative party leader in October after he lost the election to Trudeau, but opted to remain as an MP.

He showed up routinely in the House of Commons for votes, but never spoke from the floor and remained absent from most of the weekly meetings of Conservative MPs.

In his farewell remarks, Harper listed some of his proudest accomplishments, including navigating the Canadian economy through the 2008 recession and his government's tough-on-crime agenda.

"Friends, we did a lot together, but I know the best is yet to come," Harper said in the video, which appeared to have been filmed in the cabinet room on Parliament Hill — suggesting it was recorded some time ago.

Move into consulting

Harper will now make a move into consulting on international issues alongside two of his most trusted former advisers, Ray Novak and Jeremy Hunt.

The trio are listed as directors on a corporation first set up in December called Harper and Associates Consulting.

As I bid farewell to the Parliament of Canada, and prepare for the next chapter of my life, my eternal thanks to the constituents of Calgary Heritage, to the members of the Conservative Party, and to all Canadians for having given me the honour of serving the best country in the world," Harper said.

"May God bless all of you and may God bless Canada."

The party will choose a new leader next May and Harper urged conservatives to remain united.

"Our country must continue to serve as a model of prosperity and freedom," he said.

"Pursue the principles we have stood for at home and abroad, and our children, and children's children will inherit the Canada we know and love so dearly."

Harper served as a Reform MP from 1993 to 1997, before taking a hiatus from politics until 2002.

That year he was elected as the leader of the Canadian Alliance and won a Calgary seat in a byelection. In 2003, he oversaw the merger of the party with the Progressive Conservatives and in 2004, became leader of the newly formed Conservative Party.

He led the Conservatives to a minority government victory in the 2006 election and again in 2008, winning his first majority mandate in 2011 after an election that was forced by opposition parties.

Text of Harper's message

Here is the full text of Stephen Harper's statement posted to Facebook Friday:

Greetings, fellow Calgarians and fellow Canadians.

Today I wish to inform you that I am stepping down as the Member of Parliament for Calgary Heritage.

For a total of nearly 18 years, I have had the tremendous honour of representing Calgary in the Parliament of Canada. On seven occasions, I have been deeply humbled by your trust and support, time and again. And I leave elected office proud of what our team accomplished together.

We united all Conservatives behind our agenda. We cut taxes, made critical investments and balanced the national budget. We got tough on crime and put families first. We managed our G7 economy through the worst global recession since the Great Depression, and came out in the strongest position of them all. We took principled decisions in a complex and dangerous world. And, whether at home or abroad, we were always proud to stand up for Canada.

Friends, we did a lot together, but I know the best is yet to come.

Our country must continue to serve as a model of prosperity and freedom. Pursue the principles we have stood for at home and abroad, and our children, and children's children, will inherit the Canada we know and love so dearly.

As I bid farewell to the Parliament of Canada, and prepare for the next chapter of my life, my eternal thanks to the constituents of Calgary Heritage, to the members of the Conservative Party, and to all Canadians for having given me the honour of serving the best country in the world.

May God bless all of you and may God bless Canada.