Italian painter and dealer, active in England. A pupil in turn of Sebastiano Conca and Francesco Trevisani, Casali received, in 1728, his first important commission, painting the cloister of S Sisto Vecchio, Rome, which was being restored for Benedict XIII. He was rewarded for this cycle of 32 lunettes depicting the Life of St Dominic by being made a Knight of the Golden Spur the following year.
In 1729, he painted S Filippo Neri in Ecstasy for S Gregorio della Divina Provvidenza in Rome and two oval works of Franciscan saints - Margherita da Cortona and Giacinta Marescotti - facing one another in the church of S Antonio al Monte, Rieti. Casali's commissions in the early 1730s include the Virgin in Glory (1730) at Collevecchio, the Martrydom of St Cristina (1732) for the main altar of the collegiate church at Bolsena and his work for Cardinal Pietro Ottoboni's chapel of the Holy Sacrament at S Lorenzo in Damaso, Rome. This consists of an Adoration of the Mystic Lamb in fresco on the vault, since his altarpiece in oils of the Holy Trinity is now untraced.
He spent many years in the middle of the 18th century in England. From 1741 to 1766 Casali worked for Sir Charles Frederick and other patrons. In 1761 his painting the Murder of St Edward Martyr (Burton Constable Hall, East Yorkshire) was exhibited at the Royal Society of Arts where it won First Prize.