Havasi was Hungarian Champion, winning at Budapest 1922.
[1] He tied for 4-5th at Budapest 1931 (HUN-ch, Lajos Steiner won); took 4th at Sopron 1934 (Rudolf Spielmann won); tied for 5-6th at Budapest 1934 (Maróczy Jubilee, Erich Eliskases won); tied for 12-14th at Budapest (Ujpest) 1934 (Andor Lilienthal won); tied for 5-6th at Tatatovaros 1935 (László Szabó won); tied for 5-7th at Budapest 1936 (HUN-ch, L. Steiner and Mieczysław Najdorf won); tied for 3rd-4th at Milan 1938 (Eliskases and Monticelli won), and tied for 4-6th at Budapest 1939 (Dori Memorial, Balla and Szabó won).
[2] Havasi played for Hungary in Chess Olympiads: He won six team medals (three gold in 1927, 1928, 1936, and three silver in 1924, 1930, 1937) and one individual silver medal in 1935.
He published a book A soproni jubiláris sakkverseny, 1934 (Budapest 1935).
[12] During The Holocaust, Kornél Havasi was killed by the Nazis at 1945 in Bruck an der Leitha (Austria).