The son of a guerrilla leader, Xi had risen through the ranks to become party chief in Shanghai before being named Monday to the powerful Politburo Standing Committee, The Washington Post reported.
The report said he is the highest ranked among the four newcomers in the party’s new leadership lineup coming out of the just ended 17th party congress.
The other five in the nine-member committee include Hu and four other holdovers.
Under party tradition, the Post said Xi's ranking showed he is the favorite to replace Hu in 2012 when Hu’s term ende.
Next to Xi is Li Keqiang, 52, another doctorate holder who heads the party in the northeast Liaoning Province. The Post said Li had been seen as Hu's own favorite as a successor.
The New York Times reported three former members of the Standing Committee were officially retired, including Vice President Zeng Qinghong. Their exit may help boost Hu’s ability to win support in the committee for his policies.
Unlike in the past, the leadership regrouping shows the system is increasingly being governed by consensus among the party elite, the report said.