Guo Wengui, who also goes by the name Miles Kwok, reportedly started his career as a public servant in eastern China's Shandong Province. His highest-profile investment is Pangu Plaza, an office and seven-star hotel complex in Beijing that overlooks the Olympic Stadium. He also controls a business that owns a stake in China's Founder Securities. He parlayed relationships with some of China’s most powerful officials to help build a global portfolio including hotels, office buildings and securities brokerage firms. Show Mr. Guo a spreadsheet listing the shareholders of the giant Chinese company HNA, which has been buying up businesses in the West, and he’ll rattle off the names of the prominent families that he claims really control their stakes. Ask him to map out family trees for those names, the key to tracking ill-gotten wealth in China, and he’ll do it from memory, down to the sisters, the cousins and the aunts. Mr. Guo, who is a member of Mar-a-Lago, President Trump’s private Palm Beach club, is eager to get close to the powerful. On Tuesday, he wrote on Twitter that he flew to Washington for meetings at the Trump International Hotel. He contributed to charitable work by Tony Blair, the former British prime minister, who calls him a friend. Mr. Guo boasts of multiple residences around the world, including in Beijing, London, Tokyo, Abu Dhabi and Hong Kong. His oceanside home there, with sweeping views of Repulse Bay, sits on two lots that Mr. Guo’s son bought for 880 million Hong Kong dollars ($113 million) in 2011, according to property records. He says he was born in May 1970, one of 10 boys in a family with ties to the Chinese Army from a small town in eastern China’s Shandong Province. (Legal documents say he was born in February 1967.) In prison, Mr. Guo, who has only a middle-school education, learned about Chinese history and other topics from educated inmates, he said. After his release in 1991, Mr. Guo met a prominent businesswoman who introduced him to wealthy investors. Soon after he built a hotel in the central Chinese city of Zhengzhou, which became a meeting spot for government officials. Those contacts and relationships with other officials, including Mr. Ma, the spy chief, helped Mr. Guo build his empire. He expanded into finance, acquiring a large stake in a securities brokerage firm. In 2014, the Hurun Report, which tracks the fortunes of China’s elite, estimated his wealth at $2.3 billion. But that same year, Mr. Guo’s ambition to take control of one of China’s biggest brokerage firms fell apart and he had a dispute with his business partner, who was later jailed. Since then, he has lived abroad and his assets in China — he claims 120 billion renminbi ($17.4 billion) in all — have been frozen. Mr. Guo is facing financial pressures.