In January 1961, Joginder joined the 25th course of the National Defence Academy, and was still a cadet when the Sino-Indian War broke out in 1962. The deputy commandant of the NDA at the time, Brigadier Hoshiar Singh, was given command of a brigade under the 4th Infantry Division and was killed in action. Largely unprepared for war and humiliated by its defeats, the Indian armed forces underwent a large-scale expansion after hostilities ended, with emergency commissions given to several thousand candidates from 1963 to 1965. The one-year training at the NDA was shortened to seven months, as a result of which Joginder and his class were commissioned early as second lieutenants on 2 August 1964, with Joginder receiving his officer's pips from his father at the passing-out ceremony. His grandfather Atma Singh also gave him his blessing, saying, "God willing, the son of a private shall be a colonel, and the son of the colonel shall be a general!"