Meet our team.


Firefly Health is a team of leading healthcare professionals, entrepreneurs, software engineers, designers, and data scientists united in the goal of making the best healthcare accessible to the most people.

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Andy Ellner

Chief Executive Officer

Andy was the founding co-director of Harvard Medical School's Center for Primary Care, and founding director for Harvard Medical School's Program in Primary Care and Social Change. He holds an MD from Harvard Medical School and an MSc from the London School of Economics.

He is also a practicing primary care physician.

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Jeff Greenberg

Chief Operating Officer

Jeff was a founding medical director of the Innovation Hub at the Brigham and Women's Hopsitalwhere he also held several leadership positions. He was formerly a consultant with McKinsey and Co. He holds an MD from the University of Pennsylvania and an MBA from the Wharton School.

He is also a practicing primary care physician.


Justin Dangel


Justin founded and Consumer United / GOJI. He is currently the founder and chairman of Ready Responders. He has deep expertise in consumer engagement and user acquisition.

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Franklin Yang

VP of Product Strategy

Franklin was an early employee and engineer at Flatiron Health. At Flatiron, he led a team that was building the technology backbone to run clinical trials in-house.

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Luke Cheng

Design Lead

Luke did product management at Facebook and UX design at a New York agency called Huge before bringing his skill set to Firefly. His design practice focuses on crafting high-quality end-to-end user experiences while ensuring success through product strategy and service design. 

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Sherry Pagoto

Behavioral Health

Dr. Pagoto is a professor at the University of Connecticut and is the director of the UConn Center for mHealth and Social Media. Her award-winning research focuses on leveraging technology in the development and delivery of behavioral interventions targeting diet, physical activity, and cancer prevention behaviors. She also practices as a licensed clinical psychologist.

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Keith Toussaint


Keith is the founder of KMT Strategies, a healthcare consulting firm, and the Executive VP of Ready Responders. He draws on deep and broad knowledge of healthcare information systems from his roles at Mayo Clinic, Amazon Web Services, and Microsoft. 


Nisha Basu

Clinical Intelligence

Nisha is the Director of Population Management of Healthcare Associates at Beth Israel Deaconess Medical Center, where she works on creating systems change and integrations in order to deliver quality, coordinated, value-based care.
She also teaches at Harvard Medical School and is a practicing primary care physician.