The son of Ezzelino I, in 1182 he fought for lands belonging to the monks of a monastery in Sesto al Reghena.
Ezzelino raised an army to expel Azzo VI of Este after the latter became podestà of Verona in 1207.
In 1209-1210 he was among the followers of emperor Otto IV, who gave him possession of Bassano (1211).
In 1212 Ezzelino II clashed near Verona with the troops of the Lombard League; the latter was defeated and its commander, Azzo VI d'Este, perished.
His daughter Cunizza da Romano was married to Riccardo di San Bonifacio, lord of Verona.