Some of his first patronage came from works the Marquis Pieri-Nerli, who also commissioned him to paint frescoes of the four evangelists for a private chapel in his home in Quinciano, a hamlet in the comune of Monteroni d'Arbia.

Another canvas, Sira che sacrifica la propia vita for the padrona Fabiola won a medal at the Exhibition of Termini (Rome).

He painted in tempera: Love crowning the three Graces At the 1878 Turin Exposition, he sent an oil canvas depicting The Deposition of Pope Silverius by Antonina, wife of Belisarius.

Between 1882 and 1888 Maccari painted a series of frescoes depicting famous events in the history of the Senate of Ancient Roman at the "Sala Maccari" in the Salone d'Onore (Reception Hall) of Rome's Palazzo Madama, seat of the Italian Senate, amongst them his most famous work, Cicero Denounces Catiline (more on this canvas below).

Maccari's most famous work of art depicts Cicero's Oratio in Catilinam Prima in Senatu Habita, his first speech denouncing Catiline in the Roman Senate which drove him from the city (63 BC).

Maccari has been praised for the way his paintings captured the description of events and how Catiline was avoided by his fellow senators and sat alone while Cicero attacked him.