Conservative interim leader Rona Ambrose was praised by her colleagues and political opponents on Tuesday as a passionate advocate for women and girls who played a crucial role in keeping her party together after a bruising federal election loss.

Ms. Ambrose, 48, officially announced on Tuesday her intention to resign her Edmonton-area seat when the House of Commons rises for the summer, ending a 13-year federal political career that featured five senior cabinet portfolios including environment, health and public works.

"I want to say what an honour it has been to serve this great place," Ms. Ambrose said in the Commons, following a tribute from all four party leaders. "I have enjoyed every minute of it."

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Ms. Ambrose's 18-month tenure as interim leader was scheduled to come to an end on May 27 at the Conservative convention in Toronto, when party members choose their new leader from 13 candidates. But she also made a decision to bow out of federal politics altogether and start a "new chapter" with her spouse, J.P. Veitch.

Ms. Ambrose will next take a position at a think tank as a global fellow at the Washington-based Wilson Center's Canada Institute, where she will work on the bilateral trade file.

She also told Chatelaine Magazine she plans to write a children's book about the International Day of the Girl, which she helped to create at the United Nations when she was status of women minister.

Under her watch, the Conservative party has thrived both in membership numbers and financially, taking in $5.3-million in the first three months of 2017, nearly twice as much as the Liberals – and not including the $4.6-million raised by the leadership candidates vying for the job.

Conservative MPs said Ms. Ambrose's particular mix of confidence, experience, intellect and positivity – not to mention her sense of humour – helped keep the party united following the 2015 election loss and resignation of former prime minister Stephen Harper.

"It's easy to underestimate the state we could have been in. She got us all united, all on track, immediately after the election," said first-term Conservative MP Shannon Stubbs, who represents a nearby Alberta riding. "I think there are a lot of people who would have liked to see her in that permanent spot."

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In fact, there was an unsuccessful "Draft Rona" campaign, which sought to amend the party constitution to allow for her to run for the job.

"Never once did she treat this position as a placeholder or merely a fill in," Conservative House Leader Candice Bergen told the Commons.

Prime Minister Justin Trudeau praised Ms. Ambrose for serving Canadians with elegance and determination, while managing a number of portfolios.

"Throughout it all she has remained true to her own values," he said.

NDP Leader Tom Mulcair said Ms. Ambrose was his "personal favourite" Conservative leader.

"In less than two weeks, a new Conservative leader will be chosen. We don't know who that will be, but we do know it won't be Kevin O'Leary, so I guess for that at least we can thankful," he said, to laughter.

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Mr. Mulcair said he worked to help fast-track Ms. Ambrose's private-member's bill that would require judges to receive training in sexual-assault law. The bill passed in the Commons on Monday with unanimous support and now moves to the Senate.

In a statement on Facebook, Mr. Harper called Ms. Ambrose an "outstanding public servant, and a proud Conservative."

"Rona's highly capable leadership of the Conservative team has set a high bar for those who will follow," he wrote.

Ms. Ambrose made her resignation announcement earlier Tuesday during a breakfast speech at the Château Laurier hotel in Ottawa. Ms. Ambrose highlighted the "capable, strong, talented" women on the Conservative team, such as Ms. Bergen, leadership candidate Lisa Raitt and MPs Michelle Rempel and Dianne Watts. She didn't, however, mention fellow Conservative leadership candidate Kellie Leitch.

"They're amazing leaders," Ms. Ambrose said of her colleagues, adding that she didn't fill a "quota," a reference to Mr. Trudeau's gender-balanced cabinet. "We have women that can compete."

Before going into politics, Ms. Ambrose worked with organizations to end violence against women, including a sexual-assault and sexual-abuse crisis centre. But she was widely criticized by pro-choice Canadians when she voted in favour of a 2012 Conservative motion to study the legal rights of the fetus, which Ms. Ambrose connected to her concerns about sex-selective abortion.

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In her breakfast speech, Ms. Ambrose acknowledged she helped set a new tone for the party. One of her first moves was to support an inquiry into missing and murdered aboriginal women and girls.

With a report from The Canadian Press