For many Chinese, he's a curious conundrum, an emerging national figure with some serious public relations issues.
The only grandson of Mao Tse-tung, the Great Helmsman himself, Mao Xinyu's bloodlines ooze political royalty. Yet instead of praise, the 40-year-old faces ridicule as a pudgy underachiever shamelessly riding the coattails of the relative many consider this nation's greatest statesmen.
When state media reported this week that the younger Mao had become the youngest officer to reach the rank of major general in the army his grandfather co-founded eight decades ago, critics unleashed another barrage of vitriol.
Many claim one Mao in a leadership role was more than enough for China and that the military historian's rise to public prominence carries a grim foreboding. Others decry what they call state-sponsored nepotism run amok.
On Tuesday, the Internet carried unflattering pictures of Mao, an academic who has spent most of his career researching the exploits of his famous grandfather, who died in 1976. Some showed him in his military uniform, his beefy neck bulging over his collar. There was an undated snapshot of him decked out in a flannel shirt, signing copies of his book "Grandpa Mao Tse-tung"
His adversaries questioned his intelligence, and even his handwriting.
"To have such an unqualified person become a general in China's military, it's an insult to the [People's Liberation Army,]" said Pu Zhiqiang, a lawyer and human rights activist. "Those promoted in the future as generals should feel humiliated by this."
Until recently, officials had refused to confirm that the unassuming Mao had gained the rank, apparently to avoid claims of favoritism.
"This is a natural elevation. Mao's many achievements earned him the right to be promoted," Bao Guojun, a spokesman for the PLA's Academy of Military Sciences, where Mao works as a historian, told reporters this week.
Mao Xinyu's father was Mao Anqing, offspring of one of the Chairman's numerous marriages. The younger Mao graduated from the history department at the People's University in Beijing and received a doctorate from the Academy of Military Sciences. A blogger who has supported the socialist doctrine, Mao is married with two children, an anomaly in a nation with a strict one-child policy.
In an interview last fall with a Chinese newspaper, Mao spoke of his military service and famous forebear.
"It was after joining the army that I began to really understand Grandpa," he said. "As a soldier, I regard him as our leader and commander in chief."
Yet some academics question the younger Mao's achievements.
"If Mao Xinyu deserves to be a general, he needs to show us he has done something," said Liu Shanying, a professor at the Institute of Political Sciences under the Chinese Academy of Social Sciences.
"So far, we haven't seen any results from his studies. He hasn't come up with any new ideas about his grandfather's theories. From an academic view, he lacks achievement."
For years, Mao Xinyu has fiercely defended his now-controversial ancestor — considered a national hero by most but a heartless strongman by a growing number of younger Chinese.
After helping overthrow Chiang Kai-shek's Nationalists to establish the People's Republic of China in 1949, the leader known as Chairman Mao wielded unrivaled power until his death. Today, Mao's descendants play little role in state affairs.
As they rushed in and out of a city subway not far from Tiananmen Square on Tuesday, Beijing residents were mixed in their reaction to Mao's promotion.
Dressed in a flowing yellow robe, his wispy white beard blowing in a slight breeze, Buddhist monk Hong Yun said Chairman Mao had contributed so much to China that any family namesake deserved special privileges.
"He's related to Chairman Mao," said the 68-year-old Hong. "He's earned his connections."
Not far away, office worker Ji Qin shook her head in disagreement.
"Promotions and government appointments should depend on a person's ability, not their name," she said, "even if that name is Mao."
Tommy Yang of The Times' Beijing Bureau contributed to this report.