Glenn Edward Greenwald is an American investigative journalist, author, and former constitutional lawyer known for his advocacy of civil liberties and his critical stance on government surveillance, establishment media, and U.S. foreign policy. Born on March 6, 1967, in Queens, New York, and raised in a Jewish family, he practiced litigation in New York City focusing on First Amendment issues before leaving the legal field in 2005 to blog full-time on civil liberties and U.S. foreign policy matters. Greenwald gained early attention for his sharp critiques of the Bush administration's post-9/11 policies, including opposition to the Iraq War and warrantless wiretapping.

He rose to international prominence in 2013 when he collaborated with Edward Snowden to publish classified documents revealing the National Security Agency's (NSA) global surveillance programs. These revelations, published in The Guardian, exposed mass data collection by the U.S. government and its allies, earning him a Pulitzer Prize as part of the Guardian team and cementing his reputation as a prominent whistleblower advocate. In 2014, Greenwald co-founded The Intercept alongside Laura Poitras and Jeremy Scahill, funded by eBay founder Pierre Omidyar, to pursue independent investigative journalism. He departed The Intercept in 2020 following disputes over editorial independence, notably regarding his reporting on Joe Biden.

Greenwald has authored several books, including "No Place to Hide" (2014), which details the Snowden leaks, and "Securing the State" (2006), a critique of post-9/11 policies. Known for adversarial relationships with establishment figures, he has criticized politicians across the political spectrum, such as Jane Harman for supporting surveillance policies. He resides in Brazil with his late husband, David Miranda, a Brazilian politician who passed away in 2023, and holds dual U.S.-Brazilian citizenship. Greenwald's work frequently addresses the intersections of media, intelligence, and politics, emphasizing transparency and opposition to authoritarian tendencies within democratic institutions.