That was a departure from Chinaâs carefully scripted transfers of power in recent decades and a possible signal that Mr. Xi intends to govern beyond this next five-year term. Mr. Xi may also want more time to test possible successors, while avoiding lame duck status with an heir waiting in the wings.
But by discarding the unspoken conventions that have ensured relatively stable leadership changes in recent years, Mr. Xi has pushed Chinese politics into new territory that critics have warned could lead to turmoil, or a cult of personality with echoes of Mao.
âIf Xi goes for broke and breaks precedent by not preparing for an orderly and peaceful succession, he is putting a target on his back and risking a backlash from other ambitious politicians,â Susan L. Shirk, the chairwoman of the 21st Century China Center at the University of California, San Diego.
âBy taking such a risk, he shows himself to be more like Mao than we originally thought â he demonstrates his power by overturning institutions,â said Professor Shirk, a former State Department deputy assistant secretary for China policy.
In a possible nod to such concerns, most of the new Standing Committee members were not longtime associates of Mr. Xi, though all have worked with him in some capacity. Mr. Li, the premier, was once seen as a possible rival to Mr. Xi to lead the country.
Among the new members were Wang Yang, 62, a vice premier who promoted himself as a can-do reformer while party chief of Guangdong Province in southern China, and Han Zheng, a former mayor of Shanghai who is credited with guiding that cityâs emergence as Chinaâs glittering financial and business capital. Neither had a long history of working closely with Mr. Xi before he became president in 2012.
Other new members have worked alongside Mr. Xi for years. They included Li Zhanshu, his longtime friend and aide, and Wang Huning, a former professor turned party ideologue who has helped craft Mr. Xiâs speeches and reports. An expert on international politics, Mr. Wang also advised Mr. Xiâs predecessors, Jiang Zemin and Hu Jintao, and as a young scholar wrote a book, âAmerica Opposes America,â based on a six-month visit to the United States.
The seventh member, Zhao Leji, served as head of the partyâs organization department and will assume leadership of its anticorruption agency, succeeding Wang Qishan, perhaps Mr. Xiâs most powerful lieutenant. Mr. Wang has retired as scheduled, despite speculation that Mr. Xi might try to keep him on the committee.
âXi has seemingly chosen magnanimity with the list,â said Christopher K. Johnson, an expert on Chinese elite politics at the Center for Strategic and International Studies in Washington. âOf course, thatâs easy to do when youâve achieved your two core objectives â making yourself the partyâs untenured ideological arbiter and refraining from signaling the succession.â
Mr. Xiâs victory at the congress means he will welcome President Trump to China next month more confident than ever in his hold on power and in his pursuit of a more assertive foreign policy. His signature initiatives to extend Chinaâs influence overseas, such as the global infrastructure program known as âOne Belt, One Roadâ and a drive to build artificial islands in the disputed waters of the South China Sea, are likely to get a boost.
Some China watchers have said they also expect Mr. Xi to place more emphasis on overhauling the economy and cleaning up finances, after spending the past five years stamping out dissent and tightening his control over the party and the military, Chinaâs other political power center.
One sign he may do so was the promotion of Liu He, his closest economic adviser and a longtime advocate of curbing debt and financial hazards. As a new member of the Politburo, a broader 25-member council that is less powerful than its Standing Committee, Mr. Liu appears likely to wield greater influence on policy.
In his remarks Wednesday, Mr. Xi noted that next year would mark 40 years since Deng Xiaoping opened up China to market forces and vowed to âfirmly and unwaveringly deepen reform in every aspect.â
Few experts expect Mr. Xi will take big steps toward market liberalization, but many believe he must move to limit financial risk. After decades of rapid growth, China faces growing economic challenges that include mountains of debt held by local governments and inefficient state-owned conglomerates.
âHe wants a team around him that will implement his vision,â said Evan S. Medeiros, the former senior director for Asian affairs in the National Security Council under President Barack Obama. âOn economic issues, one could tentatively say that this Politburo Standing Committee is more reform-minded than the current lineup.â
The party congress, the partyâs 19th since its establishment by Marxist revolutionaries in 1921, has portrayed Mr. Xi as a transformational leader guiding the nation into a ânew eraâ of Chinese socialism. Mao unified China after nearly a century of civil war and foreign invasions, Deng brought it prosperity and Mr. Xi is said to be restoring the nation to global strength and leadership.
The congress blessed his one-man style of rule by writing his name and ideas into the partyâs constitution, in effect declaring any effort to challenge him to be an act of ideological heresy.
Under Mao and then Deng, the party struggled with succession arrangements that ended in purges and division. Then, in the 1990s, the party established a pattern of installing likely successors on the Standing Committee well in advance, with party leaders serving no more than two terms.
Mr. Xi himself joined the committee in 2007, before taking power in 2012. Before him, Mr. Hu served on the committee for a decade before succeeding Mr. Jiang.
The inclusion of one or two officials in their 50s in the new Standing Committee would have suggested they were being groomed to take over from Mr. Xi in five years. Instead, the partyâs failure to promote anyone of that age will ignite speculation that Mr. Xi wants to extend his influence beyond the end of his second term.
Chinaâs national constitution says that he cannot serve more than two terms as president, but Mr. Xi could stay on in other posts, as the party leader or chairman of the armed forces, for example, or create a new role to preserve his power. Other experts believe Mr. Xi will formally retire in five years, after selecting successors he is confident will uphold his policies.
The party has promoted a phalanx of officials loyal to Mr. Xi into the broader Politburo. About two-thirds of the 15 new members joining the body once worked under Mr. Xi or have other longstanding ties to him, including some younger leaders seen as potential successors.
They included Chen Minâer, 57, who worked as a propaganda functionary with Mr. Xi when they were both officials in the eastern province of Zhejiang in the early 2000s. Some experts had speculated that Mr. Xi might attempt to catapult Mr. Chen into the current Standing Committee, a move that would have made him the heir apparent.
Instead, Mr. Chen is one of four Politburo members under the age of 60 who could be considered a candidate to lead the country in five years â but only if Mr. Xi relinquishes control.