Redford resigned as the member of the legislature for Calgary-Elbow early Wednesday morning.
“In hindsight, there were many things I would have done differently," she wrote in an editorial letter announcing her resignation. "That said, I accept responsibility for all the decisions I have made.”
She stepped down as premier in March after questions over her travel expenses. Dave Hancock, who has been serving as premier since then, is also calling on the RCMP to investigate her use of government airplanes
Jim Prentice, Ric McIver and Thomas Lukaszuk have been campaigning for the leadership of the Progressive Conservative (PC) Party since June.
Lukaszuk says the allegations against Redford have been distracting and public trust in the party was deteriorating.
Earlier this week, Lukaszuk called on PC members of the legislature to hold an emergency meeting to discuss ousting Redford from caucus.
McIver called Redford's resignation difficult but necessary.
"We'll move forward, but we will not ignore the lessons of the past," he said. "Those that say ignore the past are doomed to repeat those mistakes.
"I will create a new culture, one where Albertans are at the top of the consideration chain and where government is a servant to those Albertans."
Prentice hopes the party can finally turn the page on the spending scandals that forced Redford from office.
"There's a certain amount of restoration of public trust that has to happen — but really Albertans are very optimistic, forward looking people."
CBC News has confirmed Prentice will not run in Redford’s riding when a byelection is called.
"I think that Alison Redford did the right thing by resigning as a member of the legislative assembly," said Prentice. "I think she did the honourable thing and you know, from my perspective, I would simply wish her and her family well as she moves forward with the next chapter of her life."
PC Party reacts
In a statement released Wednesday morning, PC Party president Jim McCormick tried to distance the party from Redford.
Redford started with "such promise," McCormick wrote, but "it was her own personal choices that led to her demise."
Representatives from all three opposition parties say that Redford’s resignation doesn’t let the PC Party off the hook.
"I think the problem goes deeper than Alison Redford,” said Alberta NDP leadership candidate Rachel Notley. “I think it runs through the Conservative Party, and I think most Albertans know that."
Mariana Mason, the president of the Progressive Conservative Association of Alberta (PCAA) for Calgary-Elbow, says she is currently out of the country and learned the news from the media.
"I am saddened by what has occurred, but am proud of the work accomplished by the first female premier of this province and the Calgary-Elbow team," she said.
Party hopes hinge on next leader
McCormick says the "circumstance" will not happen again under the next party leader. The PC leadership vote will be held next month.
"The PCAA and, indeed, all three leadership candidates, have made their positions very clear behaviour such as this cannot and will not be tolerated," said McCormick in a statement.
"The Progressive Conservative Association of Alberta is more than one person."
When Redford entered the PC leadership race in February 2011, she was seen as a long shot to win — especially against perceived front-runner Gary Mar, a former cabinet minister under Ralph Klein.
But she won on the second ballot and was sworn in as Alberta's first female premier in October 2011.
Redford fought off the surging Wildrose Party and led the PCs to another majority government in the April 2012 provincial election.
She won 77 per cent approval in a leadership review last November.
Derek Fildebrandt, Alberta director of the Canadian Taxpayers Federation, praised Redford's decision to forgo a transition allowance she's entitled to that's worth an estimated $179,000.
“She had promised never to take that, and today she has reiterated that comment, that commitment,” he said.