Constantin was the son of general Constantin Ion Brătianu[1][2] (1844–1910), who was the son of former prime minister Dumitru Brătianu. Constantin Brătianu became a Doctor of Law[1][3] and worked for the National Bank of Romania.[1] In 1938 he became General Secretary of the National Liberal Party which was led by Dinu Brătianu. Together with Dinu he tried to keep the splintered party intact during the dictatorships of king Carol II and conducător Ion Antonescu.[4] During World War II, after Antonescu was overthrown, Constantin Brătianu acted as Minister of Armaments and War Production in the military transitional governments of Constantin Sănătescu and Nicolae Rădescu from November 1944 until February 1945.[1][3]