Jim Prentice's voice cracked moments after he took responsibility for an election loss that stunned Canada and has led many to question whether Alberta's Progressive Conservative Party can ever recover.

"I am sorry I let you down as your leader," Mr. Prentice said on Thursday night in Calgary during a gloomy speech to party supporters that is likely to be his last as Premier. "I will carry those decisions and the electoral consequences of it for the rest of my life."

He had been Premier only seven months when he called an early election that humbled what was once one of the most dominant forces in Canadian politics. The Tories had held power with little opposition for 44 years. They lost 60 of their 70 seats, dropped to third-party statusand watched their leader resign as Rachel Notley's NDP swept the province.

Story continues below advertisement

In his first appearance since his concession speech on May 5, the departing Premier stuck to his script from the election. He said he needed an early election to get the "moral authority" from Albertans to push through his austerity plan – despite polls showing most Albertans rejecting the early election call, the austerity plan and Mr. Prentice.

"We have all been humbled by the decisiveness of [the electorate's] decision," he said. "I made mistakes. And there can be no doubt that 44 years was indeed a long time. However, the sun will shine again."

Ric McIver, elected on Monday to serve as the party's interim leader, warned that a tough rebuild was ahead for the