The Central Committee announced the move at the close of a four-day meeting, Xinhua reported. Xi is already on the Standing Committee of the Political Bureau.
Born in 1953, Xi has experience in many military posts and is a former officer.
He was first political commissar of the army in Zhengding County, Hebei province, from 1983 to 1985, and first secretary of committees in Ningde and Fuzhou, both in Fujian province, from 1988 to 1993.
In 1999, Xi became vice director of the commission for national defense mobilization in Nanjing and director of the Fujian commission for mobilization when promoted to acting governor of Fujian province.
After a transfer to Zhejiang province in 2002, Xi was appointed director of its mobilization commission.