During both the Sino-Japanese War (1937–1945) and the Chinese Civil War (1947–1949), Peng served in northwestern China commanding communist military forces. In 1948 he became commander of the First Field Army, a post he held until 1954. After the PRC's birth in October 1949, Peng was also appointed chairman of the Northwest Military and Administrative Committee, responsible for reorganizing the Northwest. In October 1950 he became both commander and political commissar of the Chinese People's Volunteers, who participated in the Korean War (1950–1953). On 27 July 1953 he signed the armistice agreement at Panmunjom. He returned to China in August 1953 and resumed his former posts until September 1954, when he was appointed vice premier, vice chairman of the National Defense Council, and defense minister.
Given Zhu's increased passivity because of old age, Peng became more influential in military matters. He was responsible for national defense, army training and reorganization, and the construction of defense infrastructure. He was also largely responsible for preparing for the Second Taiwan Strait Crisis of August 1958. As both vice premier and defense minister, he frequently traveled abroad. His last official assignment was to lead a military delegation to Eastern Europe during April–June 1959.
Shortly after returning, in September 1959, Peng was relieved of his two posts on charges that his military policy contained anti-CCP and bourgeois elements. Thereafter, he disappeared from public life until December 1966, when he was sentenced to imprisonment by the leaders of the ultraleftist Cultural Revolution (1966–1976). Peng died on 29 November 1974 in Beijing.
Li, Xiaobing, Allan Reed, and Bin Yu, eds. Mao's Generals Remember Korea. Lawrence: University Press of Kansas, 2001.