Just months after being pushed out of the White House, Stephen K. Bannon, President Trump’s former chief strategist, met with a fugitive Chinese billionaire at a suite in the luxurious Hays-Adams Hotel in Washington.

The billionaire, Guo Wengui, who is also known as Miles Kwok, was living in New York City and had landed on China’s most-wanted list, accused of bribery, fraud and money laundering. He was also a dissident and fierce critic of Beijing, seeking political asylum in the United States. And Mr. Bannon — increasingly obsessed with the emerging China threat — was eager to talk about the Communist Party, corruption and American naval operations in the South China Sea.

Since their first discussion in October 2017, they have met dozens of times — in Dallas, on Mr. Guo’s yacht and, more often, at the billionaire’s $67.5 million apartment in the Sherry-Netherland Hotel, overlooking New York’s Central Park. The two shared a stage two weeks ago in Manhattan, at a news conference they organized to announce plans to set up a $100 million fund to investigate corruption and aid people they deem victims of Chinese government persecution.

“We both naturally despise the Chinese Communist Party,” Mr. Guo said in an interview last week, referring to Mr. Bannon. “That’s why we’ve become partners.”