Eisenberg is known for co-founding and heading a private equity firm, Granite Capital International Group L.P. Lewis Eisenberg has a relation in American political fundraising circles. He is most notable for the various national, state, and bi-state appointments he held throughout his career, specifically 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.