Republican has been harsh critic of agency, fought Obama’s environmental regulations.

President-elect Donald Trump on Wednesday chose Oklahoma Attorney General Scott Pruitt to lead the Environmental Protection Agency, according to a transition official, turning to a climate-change skeptic and sharp critic of the agency to take its helm. As the chief legal officer of a major oil and natural-gas producing state, Mr. Pruitt, a Republican, has led legal fights against some of President Barack Obama’s most significant environmental rules, and one of his major roles as EPA administrator would likely be to try to roll back those regulations. That prospect cheered some industry leaders—many of whom have been frustrated as the Obama administration unveiled far-reaching environmental rules as part of the president’s goal of fighting climate change—while drawing objections from environmentalists concerned over Mr. Pruitt’s questioning of climate change. Harold Hamm, a top energy adviser to Mr. Trump and an ally of Mr. Pruitt’s, said Mr. Pruitt would take a different approach to the agency. “He understands the regulatory stranglehold that the EPA has had on industry during the Obama administration,” said Mr. Hamm, founder and CEO of Continental Resources, which is based in Oklahoma City. “I believe that he will work to unleash prosperity in America through the proper use of regulations and adhering to the rule of law.”

Mr. Pruitt has touted his leadership role in fighting the EPA rule that cut power-plant carbon emissions, called the Clean Power Plan, as well as an EPA measure that put more bodies of water under federal jurisdiction. Both rules have been temporarily blocked by federal courts as litigation proceeds. In choosing a legal official to head his EPA, Mr. Trump could be signaling that legal action will be central to carrying out his campaign promises to repeal a host of rules related to climate change and other environmental issues. “We’re very accustomed to the naysayers and the critics,” senior Trump adviser Kellyanne Conway said when asked by reporters about criticism of Mr. Pruitt’s selection. “Attorney General Pruitt has great qualifications and a good record as AG of Oklahoma and there were a number of qualified candidates for that particular position that the president-elect interviewed. We look forward to the confirmation hearings.” The selection of Mr. Pruitt reflects a request by some on Mr. Trump’s transition team that his cabinet—heavy on political allies and wealthy business leaders—should also include state officials and others not closely associated with the president-elect, according to two transition officials.

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