Chinese Communist Party, the most powerful position in the world's most populous country and second-biggest economy.
He is expected to become national president in March and hold both posts for the next decade.
He has risen to the top of the secretive party by presenting himself as a compromise candidate -- acceptable to outgoing leader Hu Jintao, still-influential former president Jiang Zemin, and other power-brokers.
But since he has largely kept his policy leanings to himself, how he will address China's challenges remains unclear -- even though he takes over at an uncertain time, with growth slowing as public expectations and scrutiny rise.
Xi has avoided revealing any leanings that might threaten his status as a consensus candidate, backing non-controversial policies and positions during his rise up the party ranks, said China political analyst Willy Lam.
"He's a team player. He played by the rules of the party. He's not a risk-taker. He doesn't want to take risks that might jeopardise his career."
Whatever his beliefs, few expect Xi to stray far from the Communist template of gradually opening the economy while maintaining tight political controls, especially as he will need to first consolidate power, a slow process faced by all incoming Chinese leaders.
Nonetheless he is seen as a cautious and skilful politician, able to navigate the factional divides of the party hierarchy.
Xi, a slightly plump figure typically seen on state television with a deadpan expression, rose up the party ranks mainly on China's fast-growing eastern seaboard.
As the son of the late Xi Zhongxun, a respected Communist elder, he is part of the "princeling" generation -- the privileged offspring of hallowed figures who played key roles in the revolution that brought the party to power in 1949.
China's new Politburo Standing Committee members (from L to R) Liu Yunshan, Zhang Dejiang, Zhang Gaoli, Xi Jinping, Li Keqiang, Yu Zhengsheng and Wang Qishan arrive to meet with the press at the Great Hall of the People in Beijing. Reuters photo
Despite this pedigree, Xi Jinping was "sent down" to the Chinese countryside to live and work alongside peasants, as were many young educated Chinese during Mao Zedong's 1966-76 Cultural Revolution.
His father fought alongside Mao and served as vice-premier until he fell in one of Mao's political purges, then was rehabilitated under pragmatic former top leader Deng Xiaoping.
While labouring in the poor northern province of Shaanxi, Xi joined the Communist Party and in 1975 moved to Beijing to study at the prestigious Tsinghua University.
He oversaw some of China's most economically dynamic and reform-minded areas, the eastern provinces of Fujian and Zhejiang, before briefly taking the top post in the commercial hub of Shanghai in 2007 -- earning a reputation as a supporter of economic reforms and an effective manager.
He created a stir during a 2009 speech in Mexico by scoffing at "foreigners with full bellies and nothing to do but criticise our affairs" -- many Chinese harbour resentment against the West -- but he has unusually deep US links for a Chinese leader.
As part of a research trip in 1985 he spent time in Muscatine, Iowa, deep in the Midwest, and paid his host family a return visit in February while on an official visit to the United States, where his daughter is a student at Harvard.
A reputed basketball fan, Xi also took in an NBA game, while a diplomatic cable released on whistle-blower site WikiLeaks recounted a 2007 conversation between Clark Randt, the then US ambassador to China, and Xi that revealed the future president as a big fan of US World War II films.
The cables described Xi as pragmatic yet ambitious, willing to tilt with the political winds to get ahead.
They said he was uncorrupted by money yet with a sense of political entitlement, feeling that fellow "princelings" like him "deserve to rule China".
His extended family have business interests worth hundreds of millions of dollars, according to an investigation by the Bloomberg news agency earlier this year, which said there was no indication of wrongdoing on his or their part.
Xi's public persona is given a sprinkle of glamour by his wife Peng Liyuan, who holds the rank of army general and sings songs praising the party.
Some analysts suggest Xi's status as a consensus figure could mean less paralysis between factions than under Hu, who heads a group of leaders who moved up through the Communist Youth League.
But the curtain drawn across the party and its leaders makes that impossible to predict, said Patrick Chovanec, a Tsinghua University professor.
"It would have been counterproductive for (Xi) when he was still relatively junior to show himself. The reason he has got ahead is because he is a follower and has not struck out and done something that is radically different," he said.
In this photo released by China's Xinhua news agency, China's new leaders, from left, Communist Party General Secretary Xi Jinping, Li Keqiang, Zhang Dejiang, Yu Zhengsheng, Liu Yunshan, Wang Qishan, and Zhang Gaoli, arrive for a press conference. AP Photo
Following are brief sketches of the seven members of the Chinese Communist Party's new Politburo Standing Committee, the country's most powerful body revealed in order of seniority.
LI KEQIANG: A bureaucrat with an unusually easy smile for China's colourless Communist officials, Li moves up in the party hierarchy and is due to be named prime minister in March, tasked with running the world's second-largest economy.
Vice Premier Li, 57, has held top posts in Henan and Liaoning provinces and was promoted to the Standing Committee in 2007. Long linked to outgoing President Hu Jintao, Li speaks English and has a law degree from Peking University. China's affable next premier
ZHANG DEJIANG: Born in November 1946, Zhang was installed as party secretary of the mega-city of Chongqing in February to replace disgraced Bo Xilai, whose fall amid scandal added to the usual factional uncertainty ahead of this year's reshuffle.
An economics graduate of Kim Il-Sung University in North Korea, Zhang has been vice premier in charge of energy, telecommunications and transportation since 2008.
Believed to be a protege of Jiang Zemin, he has been party boss of the economically booming provinces of Zhejiang and Guangdong.
YU ZHENGSHENG: Yu, 67, has been party secretary of Shanghai since 2007, when he replaced the promoted Xi Jinping. A previous party secretary of Hubei province, Yu studied at the Harbin Military Engineering Institute.
The son of Yu Qiwei, a party elder better known as Huang Jing, Yu is considered a Communist "princeling" and reportedly enjoyed good ties with Deng Xiaoping -- respected late architect of China's economic resurrection three decades ago -- and is friends with Deng's son, Deng Pufang.
LIU YUNSHAN: Liu, 65, has been the Party propaganda chief since 2002. A former reporter for the state news agency Xinhua in Inner Mongolia in the mid-1970s, Liu became vice party secretary for the region in 1992.
Widely viewed as a conservative. As head of the party's Propaganda Department for the past 10 years, Liu has tightened controls over domestic media even as he encouraged big state media to expand overseas to purvey the government's line.
Liu, 65, rose through the ranks in Inner Mongolia. He has a foot in each of two political camps. He started his career in the Youth League, outgoing President Hu Jintao's power base, but in the past decade also served a conservative ideology czar who was a staunch supporter of party elder Jiang.
WANG QISHAN: Wang, 64, is currently vice premier. He is a former Beijing mayor, Guangdong boss, and vice governor of the People's Bank of China.
An English speaker, he represents China in economic talks with the United States and European Union, whose leaders have praised him for his efforts to help advance economic ties.
He is reportedly married to the daughter of a standing committee member from the Deng Xiaoping era, and is often grouped with the princeling faction.
ZHANG GAOLI: Born November 1946, Zhang has been party secretary of Tianjin municipality since 2007. Trained as an economist, he spent decades in the southern business hub of Guangdong, rising to provincial vice party secretary.
Ran the booming city of Shenzhen, next to Hong Kong, in the late 1990s and later served as party secretary of Shandong province in eastern China. Reportedly a protege of Jiang Zemin and close to Hong Kong tycoon Li Ka-shing.