Dorenko, who was often referred to as "TV killer" for his ability to take down the most popular politicians, was one of the central figures behind Putin's rise to power. The TV reporter rose to prominence in the late 1990s with his muck-raking TV show against the then-Moscow mayor, Yuri Luzhkov, and former prime minister Yevgeny Primakov. Both were considered to be strong contenders for the Russian presidency and were more popular at the time than Putin.
Putin was appointed prime minister less than six months before Boris Yeltsin stepped down, paving the way for the former chief of the intelligence agency FSB to succeed him in the Kremlin. A political novice who was lagging far behind Luzhkov and Primakov in polls, Putin faced an uphill battle in the March 2000 elections.
Dorenko's weekly show on Channel One, then owned by tycoon Boris Berezovsky, criticized Luzhkov and Primakov and backed Putin. In an interview last year for the popular Russian YouTube show Dud, Dorenko admitted that his show was about "destroying" the two rivals of Putin.
"I wanted their blood," he said. "Only the people can make a person the president but our goal was to give the message to the people in a whisper." Many of the claims made on Dorenko's show proved untrue but the job was done: both Luzhkov and Primako decided not to run for president.
Dorenko turned against Putin in 2000 when he blamed the newly elected president for mishandling a submarine disaster. He was fired from Channel One shortly after the show aired. In recent years, he was editor-in-chief at the Moscow radio station Govorit Moskva and hosted a popular morning show.
Putin offered his condolences to Dorenko's family, Kremlin spokesman Dmitry Peskov told Russian news agencies. Peskov said that the president "has always appreciated his contribution to Russian journalism and his steadfast position."