His reign is notable for Venetian victories during the War of Gradisca (1617) and for the Bedmar Plot (1618), in which the Spanish ambassador to Venice, Alfonso de la Cueva, 1st Marquis of Bedmar, attempted unsuccessfully to destabilize the Most Serene Republic.
Don Giovanni | Giovanni Pierluigi da Palestrina | Giovanni Bellini | Giovanni Riggi | Giovanni Boccaccio | Pietro Bembo | Giovanni Battista Pergolesi | Giovanni Battista Tiepolo | Giovanni Battista Guarini | Giovanni | Giovanni Trapattoni | Giovanni "John the Eagle" Riggi | Giovanni Gabrieli | Giovanni Falcone | Villa San Giovanni | San Giovanni in Persiceto | Giovanni Verga | Giovanni van Bronckhorst | Giovanni Tamagno | Giovanni Pacini | Giovanni Battista Pescetti | Giovanni Papini | Giovanni Hidalgo | Giovanni Domenico Cassini | Giovanni de' Medici | Giovanni Bottesini | Giovanni Battista Riccioli | Giovanni Zenatello | Giovanni Visconti | Giovanni Schiaparelli |
Johan Ernst was granted the rank and title of General by the Doge of Venice, Giovanni Bembo.