He was born in the town of San Bellino in the Polesine region of the Province of Rovigo. He trained with Antonio Balestra of Verona. Bortoloni painted the 104-panel fresco cycle at Villa Cornaro, a Palladian villa in Piombino Dese near Padua. He also painted a ceiling in the Ca' Rezzonico. Other examples of Bortoloni's work are displayed at various monuments in the Veneto and Lombardy, including the parish churches at Castelgugielmo and Fratta Polesine, and in the ceilings at the Church of San Nicolò da Tolentino (presbytery, c. 1730) and the palazzo Ca' Vendramin Calergi. Along with Giuseppe Galli Bibiena (of the Galli Bibiena family of artists) and Felice Biella, in 1746–48, Bortoloni helped complete ceiling frescoes in the Vicoforte Sanctuary.
In Venice, he painted Glory of St Cajetan for the ceiling of the choir of the Theatine church of San Nicola Tolentini. He painted a Madonna and Saints for the Hospital of SS. Pietro e Paolo in Venice.
In Bergamo, he worked alongside the Milanese stucco-artist, Riva Palazzi, to decorate the ceiling of the choir, presbytery with figures and decoration. In Brescia, he painted a medallion for the Gallery in the house of Signori Barbisoni. In Ferrara, he painted a Glory of St Thomas Aquinas for the Cathedral and a canvas of Saints Cosma e Damiano for the Oratory of the Speziali.
In Turin, he painted for the half-dome of the apse of the church of the La Consolata. In the same church, in the third chapel on the right, he painted a fresco of St Bernard, alongside the stucco work of Felice Biella. In Mondovi, he painted in the church of the Sanctuary of the Madonna di Vico.
In Milan, in the church of San Vittore al Corpo he painted a lateral panel for the chapel of the Blessed Bernardo Tolomei. From Milan, he moved to Bergamo, where he was commissioned to paint the ceiling of the church of Santi Bartolomeo e Stefano and had made designs to paint the four quadrants of the world, as Pozzi had done for the church of Sant'Ignazio in Rome, when he developed a sudden fever and died after two days on June 9, 1750.
- *Bartoli, Francesco (1793). Le pitture, sculture ed architetture della città di Rovigo: con indici ed illustrazioni. Googlebooks. Pietro Savoni, Venice. p. 320.