1. Michael Dowling

Since he first joined North Shore-LIJ in 1995, Michael Dowling has helped it become an indisputable giant in the health care world. With 48,000 employees, 17 hospitals, the relatively new Hofstra North Shore-LIJ School of Medicine and the world-renowned Feinstein Institute for Medical Research, Dowling oversees one of the largest medical enterprises in America as well as one of the top employers in New York State. The annual operating revenue alone is $7 billion. And this native of County Limerick in Ireland is still not satisfied—he wants to grow the system even bigger. Dowling recently launched North Shore-LIJ’s own health insurance plan, and he’s helped set up a venture capital unit with hopes of tapping into high-tech development. His headquarters are in Manhasset but he’s expanded North Shore-LIJ’s reach to the five boroughs of New York City as well as New Jersey, and he’s also eyeing Westchester County and Connecticut. Dowling had five surgeries last year—two back surgeries, a knee surgery, a shoulder surgery and a pulmonary embolism—but he hasn’t slowed down for a second and there’s no end in sight.