He was born in Venice, Italy, and was in the service of Karl Philip Emanuel of Pfalz in Mannheim, Germany before being called to Denmark in 1739 to work for the royal court of King Christian VI.
The work was entitled "Uretfærdighedens og lasternes flugt for den retfærdige Guds åsyn" ("The Flight of Injustice and Vices at the Sight of the Just God"), and was painted 1739-1740.
Miani and le Clerc were both named professors at the Academy, while painter Marcus Cardes and medallionist Georg Wahl were freehand drawing teachers (informatorer).
A Royal Resolution of 24 August 1740 provided a measly subsidy of 500 Rdl from the King’s discretionary funds, and conditions at the school were miserable.
For some period of time starting in 1744 the model school, which had only 10-16 students, took place at the Widow Lyders's house on Gammelstrand where Miani was lodging.