Environment Minister Jim Prentice will be leaving the government and assuming a high-profile post in the private banking sector.

Prentice, one of the most well-known and senior ministers in the government, made the announcement in Parliament on Thursday afternoon.

Prentice, 54, said that he has accepted a new job with CIBC as vice-chairman, which comes into effect in 2011. Prentice said that he would also be leaving his seat in Calgary by the end of the year.

Prentice, who entered federal politics in 2001, said that he will be leaving his cabinet post effective immediately.

In an interview, Prentice said that he had recently been thinking of shifting gears career-wise.

"Upon reflection, I had decided that I wanted to go back to the private sector. Coincidentally, I was approached by CIBC, and one thing led to another," he told CTV's Ottawa bureau chief Robert Fife.

"So it seems the right thing to do, and my family is very supportive. I'm quite excited about the future."

Prentice said the announcement came after a meeting with the Ethics Commissioner, which presumably centred on his decision to exit his post and take up office in the private sector.

Prime Minister Stephen Harper said that his relationship with Prentice has been one of the most "delightful" of his public career.

Harper added that Prentice is one of the most well-respected MPs in Ottawa, and that he earned the "highest respect" from colleagues on both sides of the floor.

The prime minister noted that Prentice has managed a number of very important cabinet portfolios since the Tories assumed government in 2006.

In a statement released later in the day, Harper thanked Prentice for "nearly a decade" of public service.

Harper mentioned that back in 2002, Prentice "stepped aside in a by-election race" so Harper could run to become the MP for Calgary Southwest.

Prentice also chaired cabinet's operations committee, a powerful position which Harper said was akin to being the government's chief operating officer.

Government House Leader John Baird will temporarily take over the Environment post, the Globe and Mail reported.

CTV's chief parliamentary correspondent Craig Oliver said that Prentice has been unhappy with his current post, following a cabinet shuffle which pulled him out of the Industry portfolio.

"He was not happy when the prime minister pulled him out of Industry and put him into Environment," Oliver said Thursday afternoon from Ottawa.

Before entering politics, Prentice practised law in Calgary, where worked in property rights and environmental issues.

Prentice was once seen as a potential candidate to replace Harper as the Conservative leader.

However, critics have said that the government's Environment portfolio is simply an extension of policies which are drafted in Washington.

While greenhouse gas reduction was seen as a key goal of U.S. President Barack Obama during the 2008 presidential campaign, Republican gains in the House of Representatives this week have likely put those aims on the backburner.

The Canadian Press reported that Prentice has been saying privately that he didn't expect much progress in his portfolio over the next two years.

Liberal house leader and former environment critic David McGuinty said the announcement was "a big surprise."

McGuinty told CTV's Power Play that being an MP is a "tough life" with a lot of demands.

Meanwhile, NDP environment critic Nathan Cullen said that he isn't surprised that yet another new minister will take over the vacated portfolio.

"It's a nearly impossible scenario," Cullen told Power Play. "It's a burnout kind of job, being an environment minister for a prime minister that doesn't care about the environment."