John Nathan 'Janno' Lieber, born September 19, 1961, is an American lawyer, civil servant, and executive from a Jewish family noted for its political achievements. A graduate of Harvard University and New York University School of Law, he is admitted to the New York Bar. Early in his career, he served as a transportation policy advisor during New York City Mayor Ed Koch's administration and later as acting assistant secretary in the U.S. Department of Housing and Urban Development. From 2003 to 2017, he was President of World Trade Center Properties LLC at Silverstein Properties. Lieber has been involved in philanthropy as a trustee for organizations including the Fresh Air Fund (1986-1998), Project Dorot (1988-1993), Brooklyn Children's Museum (since 2002), Alliance for Downtown New York (since 2004), and New York Building Foundation (since 2007). He was appointed acting Chair and CEO of the Metropolitan Transportation Authority (MTA) in July 2021, with permanent confirmation in January 2022. Based in New York, he leads the agency responsible for much of the region's public transit infrastructure.