Maffi founded the meteorological observatory and the Museum of Natural History of Pavia, as well as serving as editor and director of Rivista di scienze fisiche e matematiche.

Maffi was later named Pro-Vicar General of Pavia and pro-synodal examiner, doctor honoris causa of theological college of Parma, and a supernumerary member of its scientific academy.

He received his episcopal consecration on the following 11 June from Cardinal Lucido Parocchi, with Archbishops Felix-Marie de Neckere and Diomede Panici serving as co-consecrators, at the Basilica of Saint Paul Outside the Walls in Rome.

[4] A close friend of the Royal Family, in 1930, he presided at the marriage of Crown Prince Umberto of Italy and Princess Marie-José of Belgium.

[2] His love for science once provoked Pisa's outrage, when Maffi proposed to erect a statue of Galileo Galilei, the scientist condemned by the Inquisition as a heretic.