Regina 'Gina' McCarthy is an American environmental policy expert and public servant renowned for her leadership in air quality and climate initiatives. Born on May 3, 1954, in Boston, Massachusetts, she grew up in the working-class Dorchester neighborhood and developed an early interest in public health and environmental protection influenced by her family's experiences in urban pollution. McCarthy began her career in local government, serving in environmental roles in Boston and later as an aide to Massachusetts Governor Michael Dukakis. She advanced through state environmental agencies, including positions at the Massachusetts Department of Environmental Protection and the Connecticut Department of Environmental Protection, where she focused on clean air regulations and hazardous waste management.

McCarthy's national prominence came during her tenure as Regional Administrator for the U.S. Environmental Protection Agency's (EPA) Region 1 (New England) from 1998 to 2009, followed by her role as Assistant Administrator for Air and Radiation from 2009 to 2013. Appointed by President Barack Obama as the 13th EPA Administrator in 2013, she served until 2017, overseeing the implementation of landmark regulations such as the Clean Power Plan to reduce carbon emissions from power plants and updated standards for ozone and particulate matter. Her tenure was marked by efforts to combat climate change, though many of her initiatives faced repeal under the subsequent Trump administration. In 2021, President Joe Biden named her the first White House National Climate Advisor, a position she held until 2022, advising on federal climate policy and international commitments like the Paris Agreement.

Post-government, McCarthy has continued her advocacy as a professor in practice at the Harvard T.H. Chan School of Public Health and a senior fellow at the Harvard Kennedy School's Belfer Center. She has been vocal on global climate challenges, emphasizing equity in environmental justice. While praised for her pragmatic approach to regulation, McCarthy has faced criticism from industry groups for regulatory overreach and from some environmentalists for not going far enough on fossil fuel phase-outs. No major legal controversies are associated with her career, though her policies have been subject to numerous lawsuits from both sides of the political spectrum.