Whether Hu Jintao is visiting farmers in remote villages or meeting heads of state, Wang Huning is usually by the president's side.
He was usually there with Jiang Zemin, too, during the latter's decade at the helm.
In fact, Wang has probably appeared in public more often than any other top official in recent years, although he rarely speaks and often goes unrecognised.
For two decades, Wang, 57, has served as a trusted adviser and wordsmith to the country's most powerful men.
He now heads the party's Policy Research Office, where his role is like a combination of national policy adviser and chief speech writer.
After becoming the mainland's youngest university professor - he stayed on after graduating from Fudan University to teach international politics in 1981 - Wang gained respect in leadership circles for his academic depth, neutral political stance and cautious working style.
"He is politically low-key, intellectually neutral and emotionally calm," said Ni Shixiong, a former dean of international politics and public affairs at Fudan University who now heads its Centre for American Studies.
Jiang reportedly first took notice of Wang after the former president's mentor, former Shanghai mayor Wang Daohan , called the promising academic to his attention.
Before entering Zhongnanhai - the party headquarters in Beijing - Wang Huning advocated continued authoritarian rule to maintain political stability while gradually introducing democracy inside the party and expanding it to the outside. Jiang, who rose to power in the aftermath of the Tiananmen Square crackdown, was particularly taken by Wang's book, New Authoritarianism, which contained ideas Jiang thought suited the country at the time, Ni said.
The former president was said to be so fond of Wang's works he could recite whole passages.
Due to his close ties to Jiang, many observers consider Wang a member of the former president's "Shanghai gang".
But his political savvy and knack for negotiating internal debate have allowed him to thrive under Hu.
"He is academically intelligent and politically smart, as he never made his view known until he was sure that others would accept his point of view," said Jin Canrong, a former classmate who is now associate dean of Renmin University's school of international relations.
Guo Dingping, a former student of Wang's, who now heads Fudan University's Centre for Japanese Studies, said: "He does not like arguing with people, though he is very assertive."
Wang's tenure as a top adviser has coincided with the party's decades-long focus on economic development over ideological debates, culminating in the country's emergence in 2010 as the world's second-largest economy.
Wang played an important role in crafting Jiang's "Theory of the Three Represents" as well as Hu's "scientific theory of development", both of which have been written into the party's constitution.
Jiang's theory - introduced in 2000 - rules out the development of a multiparty political system and instead advocates expanding the party's membership to include people from different social classes, including businesspeople.
"Wang knows a lot about Western politics and Marxism," said Mao Shoulong, a professor of public administration at Renmin University.
Mao said Wang believed that a political regime should suit the nation's productivity. But he is not sure how much Wang's ideas have influenced the leadership.
"It's hard to say the role of the scholar," Mao said. "We cannot say he himself solely crafted the theories."
Born in 1956 in Shanghai, Wang was spared being sent to rural villages during the Cultural Revolution due to health problems. He studied French at Shanghai Normal University and enrolled in a graduate programme in international politics at Fudan University in 1978.
Wang became a professor immediately after graduation and spent time as a visiting professor at the University of California, Berkeley, in the late 1980s.
He was appointed dean of the international politics department at Fudan University in 1989 and led its law school for a stint ending in 1995. Wang obtained a measure of fame in 1993, when the university debating team he coached won an international competition in Singapore. Along the way, he has married twice.
Despite his academic achievements, Wang's rise to a top position in the government has surprised his peers.
Most top government officials on the mainland have had to work their way up through the party system, starting at the grass- roots level. "It's not common in China to rise from a professor directly to a senior post," said Mao. The systems of countries such as Japan and the United States allow scholars to move freely between academia and the government, "but China is different", Mao said.
Wang appears to have grown disconnected from his academic roots since joining the government.
His former colleagues and students say they rarely hear from him and he did not attend a recent gathering in Beijing for alumni from his Fudan University classes. That is in contrast to what Wang wrote in Political Life, a memoir published before he joined the central government in 1994. Back then, he said his goal in life was to keep writing books and teaching students.
But Guo, his former student, said Wang's apparent eagerness to work with the president was not surprising.
"As a scholar, his top priority was to do research," Guo said. "But a scholar would certainly want his research to be adopted [as policy]."