CHARLESTON, SC; COLUMBUS, OH — As the national law firm Shumaker continues to grow, the firm is announcing new leadership roles. The Management Committee has selected G.P. Diminich to serve as Managing Partner of the Charleston, S.C. office and Michael (Mike) J. O’Callaghan to serve as Managing Partner of the Columbus, Ohio office.

“In South Carolina, we just expanded our Charleston office, and G.P has helped drive much of that growth,” said Shumaker Management Committee Chair Jennifer Compton. “With a track record of success at the highest levels, we know G.P. will continue this momentum in 2023 and beyond.”

“Mike is a trusted advisor with an impeccable reputation—ranked a ‘Best Lawyer in America’ for the past 10 consecutive years,” said Shumaker Management Committee Vice Chair Jaime Austrich. “We are confident he will do great things for our team and clients in the Buckeye State.”

G.P. serves as the firm’s Wealth Strategies Regional Service Line Leader. He is renowned for his private wealth management work, named as a leader in Chambers High Net Worth Guide from 2018 to 2022. He routinely represents high-net-worth individuals, corporations, and privately held businesses on a variety of sensitive and complex estate and business planning matters, including taxation; mergers and acquisitions; business litigation; estate planning and probate administration; probate and estate litigation; tax controversy; and real estate planning.

Mike serves as the firm’s Environmental and Energy National Service Line Leader. His practice specializes in environmental law, workplace health and safety matters, and real property litigation. In addition, he regularly represents clients in a variety of commercial transactions involving environmental issues, including due diligence in mergers and acquisitions and brownfield redevelopment projects.