By Nia Williams

(Reuters) -The Alberta government on Wednesday appointed former Canadian Prime Minister Stephen Harper as chairman of the Alberta Investment Management Corp, after dismissing the entire board earlier this month because of low returns.

AIMCo is the public pension fund manager for Alberta, Canada's main oil-producing province, and manages more than C$160 billion ($114.36 billion) in funds.

Harper is a former Conservative Party leader and was prime minister of Canada for nine years, until his party was defeated by Justin Trudeau's Liberals in 2015.

"His appointment, and that of the rest of the board, are a strong step forward in giving all Albertans confidence in the long-term sustainability and success of AIMCo," Alberta premier Danielle Smith said in a statement.

AIMCo's operating costs, management costs and staffing have outpaced returns in recent years, prompting Alberta to take steps to overhaul the board and reset AIMCo's focus, the government said.

Going forward, the province's deputy minister of Treasury Board and Finance will have a permanent seat on the AIMCo board to improve communication between the pension fund manager and the government.

Neither Harper or the deputy minister will be paid for their AIMCo board roles.

"I am taking on this role, and doing so on a pro-bono basis, because I believe it is a meaningful act of public service to my adopted home province of the last 46 years," Harper said in a statement.

The Alberta government said it has also made additional board appointments, including three board members who were reappointed after being fired.

($1 = 1.3991 Canadian dollars)

(Reporting by Nia Williams in British Columbia; editing by Jonathan Oatis)