Mihailo Konstantinović is well known to the Serbian and Yugoslav audience as one of the greatest civil law lawyers of his time. He was active in the state administration immediately before and after the Second World War: first, as a minister in the Cvetković-Maček Government, 1939-1941; then, as a chairman of the 1946 Constitution-Drafting Committee. Prior to the Second World War, he was also legal sciences teacher to Crown Prince Petar Karađorđević II. However, Mihailo Konstantinović was also a politician in the best meaning of that term, a true statesman, more specifically, the chief architect of the 1939 Cvetković-Maček Agreement, which represented an attempt to save the Kingdom of Yugoslavia from breaking up. This article aims to shed light on the role he played in the state redesigning of the Kingdom of Yugoslavia and on the complexity of his personality, which was revealed through this role.