HARRISBURG — Gov. Tom Corbett’s often-combative environmental protection secretary will leave the post next month after two years of guiding the agency that regulated Pennsylvania’s natural gas boom amid clashes with environmental advocates, federal regulators and Democratic lawmakers.

Michael Krancer, who was a state environmental law judge and lawyer for energy giant Exelon before joining the Republican governor’s administration, helped oversee Corbett’s Marcellus Shale Advisory Commission and handled emerging issues of river and air pollution as Pennsylvania worked to modernize its laws to address new drilling and hydraulic fracturing techniques.

Corbett said Krancer, 55, of Bryn Mawr, will return to private law practice after April 15 with the Philadelphia-based firm Blank Rome, where he will serve as chairman of the firm’s energy, petrochemical and natural resources practice. Krancer may yet seek public office again: He ran unsuccessfully for the Pennsylvania Supreme Court in 2007 and his father was a generous donor to Corbett in the 2010 campaign.

Christopher Abruzzo, one of Corbett’s deputy chiefs of staff, will serve as acting secretary until a successor is named, Corbett said. Corbett, who is viewed as a close ally of the natural gas industry, was urged by Myron Arnowitt, of the environmental advocacy group Clean Water Action, to find a replacement who “knows their job is to protect our air and water, not to protect the gas industry.”

For Krancer, dust-ups were not unusual in the high-profile task of managing the rapidly expanding drilling and gas production that made the Marcellus Shale the nation’s most productive natural gas reservoir.

He frequently accused the U.S. Environmental Protection Agency of overstepping its boundaries when it came to regulating the natural gas industry in Pennsylvania, and his exchanges with Democratic lawmakers during legislative hearings were sometimes hostile.

Environmental groups regularly accused him of siding with the natural gas industry, such as the way his agency decided to regulate air pollution from drilling sites and compressor stations.