Ed Schultz, a fiercely liberal television and radio host, died Thursday in Washington, D.C., at 64.

The former MSNBC host’s death was confirmed by his current employer, the Russian-backed media organization RT America.

“Ed Schultz, host of ‘News with Ed’ on RT America, passed away on July 5 at his home in Washington, D.C.,” RT America said in a statement Thursday. “This announcement comes as a shock to all of us.”

His son, David Schultz, told the Associated Press that his father died of natural causes.

“He was an unbelievable father and husband,” his son said. “His family and friends are extremely, extremely sad right now. And we thank everyone for their thoughts and prayers, as well as privacy for our family though this time.”

Schultz hosted “The Ed Show” on MSNBC from 2009 to 2015. His radio show, “The Ed Schultz Show” ran from 2004 to 2014. He began his career as a local sportscaster and then conservative radio show host out of Fargo, N.D. According to Shultz’s former employer, WDAY, he even considered a run for Congress as a Republican in 1994 after becoming tired of “socialist” politics.

His politics began to shift, however, and in 2000, Schultz officially became a Democrat. As he became a self-identified “lefty,” Schultz appealed to liberals who identified with the plight of the working class and the decline of American trade unions.

Schultz was a controversial figure at MSNBC. In May 2011, the cable news network suspended him for one week without pay for calling conservative talk show host Laura Ingraham a “right-wing slut.”

Schultz’s move to RT America was not without controversy, either. The Kremlin-funded network, formerly known as Russia Today, registered in 2017 as a “foreign agent” with the Department of Justice after a U.S. intelligence report found the media organization to be part of “Russia’s state-run propaganda machine” and that it was part of Russia’s effort to sway the 2016 U.S. presidential election.

“We are devastated by the news of the sudden death of our brilliant anchor, one of the best TV journalists in America, Ed Schultz,” said RT Editor in Chief Margarita Simonyan Thursday. “When the campaign against RT America began and the channel was forced to register as a foreign agent, Ed set an example for all of us, saying: ‘Let them call me what they want, I am going to speak the truth no matter what.'”

Before his career in broadcasting, Schultz was a college football player. In 1977, he led NCAA Division II in passing while quarterback at Minnesota State University-Moorhead.

Schultz is survived by his wife, Wendy, and six children.

Contributing: The Associated Press