He was born in the late 14th century, the son of Dolce I and Battista Orsini, and in the early 15th century inherited large possessions in the northern Latium. In 1431 he entered the service of Pope Eugene IV, warring against the Colonna. He was a fierce enemy of the Prefetti di Vico.
In 1433 he fought against the troops of Niccolò Piccinino and, the next year, against Francesco I Sforza. Later, with the help of Giovanni Vitelleschi, he managed to destroy forever the power of the Prefetti di Vico in northern Latium. After a failed attempt to free Vitelleschi, who was prisoner at Castel Sant'Angelo (1440), he was hired by Cardinal Ludovico Scarampi, for whom Everso fought Piccinino and Alfonso V of Aragon. During the struggle between the Papal States and Sforza, he sided with the former.
In 1448 he besieged Piombino, helping Rinaldo Orsini, who was attacked by the Aragonese. The latter, anyway, hired him four years later to fight the Papal troops in the Marche, Everso being excommunicated by Pope Nicholas V.
Later, during the reign of Calixtus III, he was in conflict with Napoleone Orsini, the two being pacified by the new pope Pius II. However, when the pope contested with him the possession of Vico, he sided with Piccinino and conquered Assisi, Nocera Umbra and Viterbo. He also planned to capture Rome itself during Pius' sojourn in Siena. In 1461 Everso planned to kill the Pope, but in vain.
He died in his lands in 1464.