Zhong Nanshan, despite his advanced age, was appointed to lead the National Health Commission's investigation into the new virus, which has rattled millions of Chinese who are traveling for the week-long Lunar New Year holiday, which starts on Saturday, and jolted global markets.
His announcement on Monday that the virus could spread between humans - local officials had previously said the possibility of such transmission was limited - ratcheted up worries about the outbreak. The same night, Chinese President Xi Jinping called for resolute action to curb the spread.
Zhong, who is also well-known for his muscle-bound physique - photos of him lifting weights are widely circulated online - became a household name in 2003, when China was accused of covering up a major outbreak of Severe Acute Respiratory Syndrome (SARS).
On Tuesday, he told a press briefing in the southern city of Guangzhou, where he is based, that the government had been forthright about reporting cases and has been transparent in managing the outbreak.
Early on Thursday, officials in Wuhan, a metropolis of 11 million people, closed off transport links to prevent the spread of the virus - a move that sources said Zhong had advocated for.
Zhong and the National Health Commission could not immediately be reached for comment.
During the new virus outbreak, Beijing has warned officials that they face public shame if they cover up any infections.
"DARING TO SPEAK"
That marks a departure from 2003, when in an atmosphere of fear and suspicion, Zhong, a respiratory diseases specialist, gave media his candid, pessimistic assessment of the severity of the SARS crisis.
Footage from the time shows him telling journalists how little was then understood about SARS' source, transmission and treatment.
In a 2016 documentary by state broadcaster CCTV, which praised Zhong for "daring to treat and daring to speak," Zhong recalled a journalist asking amid the SARS outbreak whether the disease was under control.
"I couldn't help myself. I said it's not at all under control."
As many as 774 people died in the SARS epidemic, which reached nearly 30 countries.
Zhong was instrumental in China's efforts to understand and combat the virus.
While SARS left China's health authorities struggling to rebuild public trust, Zhong was hailed for his integrity and has remained a public figure ever since, weighing in on public health issues such as air pollution and food safety."What's the point of being the world's number one in GDP if eating, drinking, and breathing are all in doubt?" he said in an interview with Chinese media in 2013.