"There is no need to promote the donations we make, but the Harvard gift has caused a buzz among [internet users] and I am forced to elaborate a bit," he said.

Chan is known for his loyalty to Chief Executive Leung Chun-ying, evident last year when he called Financial Secretary John Tsang Chun-wah "a big sinner" for his unwillingness to spend money on Hong Kong's development. Tsang said the accusation was "too much".

Now 64, Chan, an American citizen born in Hong Kong, has deep connections in US business and politics.

He was embroiled in controversy in 2001 when the US energy firm Enron went bankrupt in an accounting fraud scandal while Chan served as a director at the company and a member of its audit committee.

"Ronnie Chan is a positive volcano of energy, entrepreneurship and ideas," said Thomas Plate, a syndicated American columnist, author and professor who has known Chan for more than two decades. "He has been one of my unofficial tutors in the sense of helping [me] understand the contemporary complexities of Asia, especially of China."

The Chan family has pledged to spend its fortune on helping others.

"We started donating our family wealth even before [Microsoft founder] Bill Gates and [Berkshire Hathaway chairman] Warren Buffet," Chan said, referring to the Morningside Foundation he and brother Gerald Chan Lok-chung established in 1986.

The US$350 million gift to the Harvard School of Public Health was the biggest ever for both Harvard and Morningside. The US$20 million gift to the University of Southern California's occupational science and occupational therapy programme was the largest in the field's history.

The universities will recognise the gifts by honouring Chan's parents. Harvard will change the school's name to Harvard T.H. Chan School of Public Health, after Chan's late father, Chan Tseng-hsi. The University of Southern California will rename its programme to USC Mrs T.H. Chan Division of Occupational Science and Occupational Therapy.

Ronnie Chan said the donations reflected the value the family placed on education and public health.

Gerald Chan earned his master's and doctoral degrees from the Harvard School of Public Health in the 1970s. Ronnie Chan is a trustee and holds a master's degree from the University of Southern California. His two sons, Adriel and Adley, graduated from the same university.

Adley Chan, who earned his bachelor's, master's and doctoral degrees in occupational therapy, recently joined the division as a clinical faculty member.

Morningside Foundation is part of Morningside Group, a global investment fund with private equity and venture capital investments in biotechnology, information technology, clean energy and property.

It is known for investing in half of the mainland's biotechnology start-ups and in smartphone maker Xiaomi.

Chan said even the family's stakes in Hang Lung Group and Hang Lung Properties were part of Morningside Group's assets.

As of Friday, Hang Lung Group and Hang Lung Properties were worth a combined HK$163 billion in market capitalisation.

Hang Lung is one of the biggest property developers in Hong Kong, rivalling Li Ka-shing's Cheung Kong, Lee Shau-kee's Henderson Land, the Kwok brothers' Sun Hung Kai Properties, Henry Cheng Kar-shun's New World Development and Robert Ng Chee Siong's Sino Land.

The Chan family's fortune has not always been so vast. Chan's late father, who was born in Guangdong but raised up in Tianjin , founded Hang Lung in Hong Kong in the 1960s. After fast growth during the city's economic takeoff in the 1970s, the group went through a lean period in the early 1980s, when the property market sagged.

In 1991, Chan took over Hang Lung and spearheaded a HK$92 billion investment plan. The company sank almost half of that into high-end shopping centres on the mainland, targeting major population centres.

But now that he's focusing on charity, Chan said he spent "100 times" more time on the mainland than abroad, "not seeking to meet state leaders" but overseeing his charity projects.

"It does not matter how much we donate; it matters whether the donation is meaningful," Chan said. "How to define meaningful? Let society and history judge."

While Chan's China Heritage Fund underwrote an 18-year preservation project at Beijing's Forbidden City, the foundation's focus remains on education and public health.

The Morningside Foundation has sponsored hundreds of students at mainland universities since 1996.

Despite some rewarding moments with sponsored students, Chan said the process of making donations to organisations on the mainland, which started about a decade ago, was far more complicated than working with those overseas.

In some cases, it was like "asking for trouble", he said. Bureaucracy and corruption were to blame for the hurdles, but the overall situation has improved in recent years, he said.

And at an age when his counterparts have succession plans in place, Chan leaves "tomorrow to tomorrow".

Ronnie Chan

64

Chairman, Hang Lung Group and Hang Lung Properties; co-founder, Morningside Group; vice-president, Hong Kong Real Estate Developers Association; co-chairman of the board, the Asia Society

Master of Business Administration, University of Southern California

Married, two sons