Greenberg founded the Center on National Security at Fordham University School of Law in September 2011, and currently serves as its director as of 2020.

[3] Additionally, Greenberg oversees both The Soufan Group Morning Brief and The Cyber Brief, which are email newsletters distributed to the Center's subscribers daily and weekly respectively.

She previously taught at Bard College and served as Vice President for Programs at the Soros Foundation.

Greenberg has written extensively on the Guantanamo Bay detention camp, terrorism, civil liberties, and U.S. national security.

Greenberg served as executive editor for The Terrorist Trial Report Card 2001-2011, an exhaustive study of the U.S. government's record of terrorism prosecutions since September 11, 2001.