In his time here, the high-profile health commissioner sought to expand his agency's mandate beyond its traditional role of combatting communicable diseases to fighting more chronic health problems. Conservatives, libertarians and some business people have objected to what they consider his activist adventures: banning smoking in bars and restaurants, exiling transfats from food-service fryers and baked goods, posting calories in chain fast-food joints.
(Frieden is equally unpopular on the far left for his willingness to close health clinics and his efforts to make it easier for doctors to test patients for HIV.)
Frieden's detractors are cheering his departure but they might want to hold off popping the champagne. Frieden has been who he is, because Mayor Bloomberg is who he is: the namesake of the Johns Hopkins Michael Blomberg School of Public Health. He believes Frieden's prescriptions are crucial to improving health and are just what government should be doing. And Bloomberg probably isn't going anywhere anytime soon.
Whatever mandate Frieden has requested from President Obama and whatever support he gets moving forward, Frieden is unlikely to have as strong an ally in the White House as he's had in City Hall. But he's worked extensively with the CDC and the National Institutes for Health, as well as with the new head of the FDA, Dr. Peggy Hamburg, so he won't be a novice in the political landscape. All eyes in the public health world -- and among the corporate manufacturers of food and tobacco products -- will be looking to see how hard he pushes his local agenda on the national stage. Will he go coast-to-coast curtailing smoking and transfats? Will he try to spearhead a tax on soda and junk food? Will he require doctors with electronic medical records to share their 'performance stats' with public health agencies?
Possibly, but in the immediate future he'll be busy trying to reform an agency of 7,800 employees, many of them demoralized by the management of the outgoing chief, and he'll have plenty to do, preventing the spread of pandemic flu and other illnesses.
And what about the city agency he leaves behind?
Mayor Bloomberg has said he'll announce Frieden's successor next week. There are certainly many veteran candidates within the Health Department. But Frieden's elevation to one of the top disease control and prevention positions on the planet will make the job he's vacating more attractive than ever to public health up-and-comers far and wide.