Lewis Michael Eisenberg (born 1942) is an American financier and investor who is the United States Ambassador to Italy.
He is known for co-founding and heading private equity firm Granite Capital International Group L.P.
He has a multi-decade history in American political fundraising circles and has held a number of national, state, and bi-state appointments throughout his career, including serving as the Chairman of the Port Authority of New York and New Jersey at the time of the September 11, 2001 attack of the World Trade Center, which the Port Authority operated.
In July 2017, Eisenberg was named as President Donald Trump's nominee to become the United States Ambassador to Italy.