Blumenthal has broadcast on RT (formerly known as Russia Today) on many occasions. In December 2015, during a trip to Moscow presumed by multiple sources to have been paid for by the Kremlin, Blumenthal attended RT's "10 Years On Air" anniversary party attended by President Vladimir Putin, then-Lieutenant General Michael Flynn of the United States and English politician Ken Livingstone. In an interview with Tucker Carlson on Fox News in November 2017, Blumenthal defended RT against "the charge that it’s Kremlin propaganda." He has also contributed on multiple occasions to "Sputnik" radio, as well as to Iran's Press TV and China's CGTN. Blumenthal founded "The Grayzone" website a month after his visit to Moscow. In an October 2019 article for "New Politics" magazine, Gilbert Achcar wrote that Blumenthal's "Grayzone", along with the World Socialist Web Site, has "the habit of demonizing all left-wing critics of Putin and the likes of Assad by describing them as 'agents of imperialism' or some equivalent".