Almost immediately after ending his White House employment, Stephen K. Bannon, the former chief strategist to President Trump, forged a lucrative financial relationship with a mysterious Chinese billionaire who was sought by Beijing for extradition from the United States.

China’s government had already accused Guo Wengui, a real estate magnate also known as Miles Kwok, of money laundering, bribery and rape when he and Mr. Bannon developed a mutually beneficial relationship that began with a $150,000 loan to Mr. Trump’s onetime confidant, according to a memo written in May 2019 and obtained by The New York Times.

It escalated to a yearlong million-dollar contract, for which Mr. Bannon promised to introduce executives of Guo Media to “media personalities,” according to the news outlet Axios.

Mr. Guo has denied accusations of lawbreaking and says Beijing’s extradition request is retaliation for his outspoken criticism of Chinese corruption. He has forged relationships with China hard-liners like Mr. Bannon in the United States, has a membership to Mr. Trump’s Mar-a-Lago club in Palm Beach, Fla., and is seeking asylum while in the United States staying at his palatial apartment overlooking Central Park.