ROME — Marcello Foa has spread the claim that Hillary Clinton attended a satanic dinner. He broke the news on his blog of a full-scale American military mobilization that never happened. A fan of the Russian leader Vladimir V. Putin and a guest on Russia Today, he doubts the evidence that Moscow’s operatives poisoned a former Soviet spy because it is “too obvious.”

Mr. Foa is also now the Italian government’s most influential media figure.

On Wednesday night, leaders of Italy’s populist government cheered as a parliamentary committee approved Mr. Foa as chairman of Italy’s state broadcaster RAI, which has millions of viewers, thousands of employees and is, in Mr. Foa’s estimation, the most powerful cultural force in the country.

Supporters of Mr. Foa argue that he is an independent voice free of institutional allegiances and RAI’s insidious establishment bias against populist voices. His critics argue that his right-wing politics, euro-skepticism, concerns about the “damaging” effects of combination vaccines, and tendency to re-tweet conspiracy theories should have disqualified him for the job.

But he was the pick of Matteo Salvini, the powerful leader of the anti-immigrant League, who Mr. Foa helped introduce in March to Stephen K. Bannon, President Trump’s former senior adviser. He also has ties to Mr. Salvini’s coalition partners, the Five Star Movement.