Alberta's Deputy Premier Dave Hancock will be interim premier once Alison Redford's resignation takes effect Sunday.

The long-time Edmonton MLA will hold the province's top job until the Progressive Conservative Party selects a new leader sometime within the next six months.

Hancock, 58, was selected leader of the party at a Tory caucus meeting Thursday morning. He will be sworn in as Alberta's 15th premier on Sunday evening.

Hancock has been Redford's closest supporter over the last four weeks, rising to her defence in the face of party and public criticism.

"Caucus has come together very well," he said. "Caucus understands they have a job to do and that is to provide good solid government."

He said his role will be to ensure the government gets back to its agenda and passes this year's budget, the first surplus budget in more than six years.

PC Alberta president Jim McCormick congratulated Hancock.

"Dave has been a stalwart in the PC Party since his arrival, and he brings a nearly unmatched level of expertise from all areas of the government.

“He’s an excellent choice as our interim premier, and I look forward to seeing where he will lead this province.”

Redford announced her resignation on Wednesday after months of caucus turmoil and public agitation over her travel expenses.

MLA staying an independent

The change is not enough to entice Calgary MLA Donna Kennedy-Glans back to caucus.

Alison Redford arrived at the Alberta legislature on Thursday with her daughter, Sarah. (CBC) "Right now I'm going to stay as an independent," said the former associate cabinet minister who left the caucus Monday.

"I made the choice to cross the floor based on input from my constituents. And I would only make the choice to go back to the Conservative party with that direction from my constituents."

Kennedy-Glans said she'll spend the upcoming two-week break talking to people in her community.

As for the impending leadership race, Hancock said he will not be one of the challengers.

Gary Mar, the former cabinet minister in Ralph Klein's government who won the most first ballot votes in the last leadership race, has confirmed to CBC News that he won't run for leader this time.

Mar is Alberta's trade representative in Hong Kong. He said in a statement that he is honoured to serve in that position and Alberta exports to the region have significantly increased since he started.

Service Alberta Minister Doug Griffiths also ran in the last leadership contest. However, a conversation with his son is making him doubt whether he will run this time.

"He got all teary-eyed and said, 'I don't want to miss you, Dad,'" he said.

Labour minister Thomas Lukaszuk isn't ruling it out.

“Probably any serious contender will take at least a few days to think about it and I definitely will not discount the possibility," he said.

The date of the leadership vote hasn't been set but has to take place within six months of the party leader's resignation.

Until then, the government will remain in disarray, according to Wildrose Leader Danielle Smith.

"Deputy ministers are going to be paralyzed, they're not going to make decisions, so for six months, everything is on hold while the PCs sort out their internal bickering," she said.

Redford will stay on as the MLA for Calgary-Elbow. She was seen walking to her office at the Alberta legislature with her daughter on Thursday but didn't stop to take questions.