He is a former investigative reporter at CNN,[1] and has also written for numerous other publications including The Daily Telegraph, Foreign Affairs, The Wall Street Journal, The Guardian, Slate, The Weekly Standard, and The New Republic, among others.

Weiss currently serves as the editor-in-chief of the English edition of The Insider,[5][17] which specializes in Russia related investigative journalism, fact-checking and political analytics.

A 2024 investigation into Havana Syndrome, conducted by The Insider in collaboration with the U.S. network CBS and the German news magazine Der Spiegel, led to senators calling for the case to be reopened in a joint letter to U.S. President Joe Biden.

[8][20] Weiss is a regular guest on network TV, including on Wolf Blitzer’s The Situation Room, Anderson Cooper 360°, and CNN Tonight with Don Lemon.

Brutal occupation of Cyprus, subjugation of a Kurdish minority in everything from politics to linguistics, and ongoing denial of the Armenian genocide are evidently Maastricht-compatible initiatives to the new British prime minister".

[24] In March 2015, in a commentary piece cowritten with U.S. army intelligence officer Michael Pregent for the international affairs journal Foreign Policy, Weiss accused Iran-backed Iraqi Shia militias of committing extensive atrocities against Sunni civilians in the course of their war against the Islamic State of Iraq and the Levant.

According to these reports, Weiss wrote, the militias were "burning people alive in their houses, playing soccer with severed human heads, and ethnically cleansing and razing whole villages to the ground.

[28] In 2012, Weiss served as co-chair of the Russia Studies Centre at the trans-Atlantic foreign policy think tank Henry Jackson Society.

The recommendations were criticized in an article written by James Carden – executive director of the lobbying organization[44][45][46] American Committee for East–West Accord – in The Nation as a "censorship campaign.

"[47] Another report, published in 2015, was titled “An Invasion by Any Other Name: The Kremlin’s Dirty War in Ukraine.”[48][49] It was co-authored with James Miller, Pierre Vaux, and Catherine A. Fitzpatrick.

[51][52] He was described in 2017 by a CNN executive editor as having “deep knowledge and an extensive source network in two key areas of focus right now: The Middle East and Russia.”[1] He is married to Amy Thirjung.