Brian Mahanna, the current chief of staff and deputy attorney general to New York Attorney General Barbara Underwood, said he plans to leave the public sector and join Wilmer Cutler Pickering Hale and Dorr as a partner in its New York City office in February.

Mahanna, who also once served as senior adviser to former New York City Mayor Michael Bloomberg, will be a member of the firm’s Regulatory and Government Affairs Department, where he will help clients manage high-profile crises and other challenges involving regulators.