Corporation Counsel Michael A. Cardozo, already the longest serving chief of what is now a 650-lawyer office, informed his staff Wednesday that he will be staying on for a third term as New York City’s top lawyer.

Mr. Cardozo, the city’s 77th corporation counsel, said in an interview Wednesday that he is looking forward to tackling the “enormous challenges” the nation’s fiscal crisis poses for both the Law Department and the city as a whole.