Atlantic City-based Cooper Levenson—a go-to law firm on gambling issues within its home base and beyond—is expanding into the Big Apple with the rehire of a former firm partner.

Joseph C. Mahon, a trusts and estates lawyer, returned to assume the role of lead attorney for the firm's New York City office, to be located at 45 Rockefeller Plaza.

Mahon was a partner at Cooper Levenson from 2001 to 2010, specializing in estate planning and wealth management. He left in 2010 for Frankfurt Kurnit Klein & Selz in New York, where he was a partner.

The New York expansion adds to the firm's offices in New Jersey, Delaware, Florida and Nevada.

As gambling and other gaming issues, including online and sports wagering, have exploded nationally, the firm that was founded in 1957 in Atlantic City has grown with it. Cooper Levenson has become known as “one of the premier gaming, casino, and iGaming law firms in the country,” and also handles tax and business law, estate planning and administration, litigation, labor and employment law, and health care law, according to the firm's news release on Tuesday announcing the New York addition.

It is often the law firm cited on major cases involving casinos in the region, such as the recent Appellate Division ruling on May 20 in the “Borgata Babes” case over personal appearance standards at Atlantic City's most profitable casino. Cooper Levenson is representing the Borgata in the case, which, after a decade, is set to go to trial.

“Having a physical location in New York City will enable us to better service our present and future national and international clients,” said firm CEO Lloyd D. Levenson in a statement.

Levenson said on Wednesday that his firm convinced Mahon he could stay in New York while also returning to practice for Cooper Levenson.

In his new role, Mahon will continue his work of more than 25 years advising executives, business owners and high-net-worth clients on a range of issues, including: estate planning, estate, gift and income tax planning, generation skipping transfer tax planning, state death taxes, and family governance.

In his career, Mahon has also advised clients on trust and estate litigation and dispute resolution, including contested guardianships, and on tax and other issues unique to non-U.S. persons and assets, according to the firm.

He earned his J.D. from Rutgers Law School-Newark and LL.M. in taxation from New York University School of Law.