Born in 1884 in Milan, heir to the pharmaceutical company C. Erba. Privately initiated to his studies, in the years around 1900 he decided to devote himself to art in the future.
At the age of twenty he made his first oil work. Around the same time he enrolled, at the behest of his father, at the University of Genoa at the Faculty of Chemistry, as was the family tradition. The intertwined relationships with the Milanese anarchist circles provoke the tightening of relations with the family, with the consequent abandonment of the Faculty of Chemistry. Between the end of 1906 and the beginning of 1907, Carlo definitively abandoned his university studies and returned to Milan.
In November 1908, Erba enrolled in the courses of the Free Nude School annexed to the Brera Academy. He befriends Carlo Carrà and other artists. Carlo's father, who does not accept his son's decision to abandon his studies to devote himself to painting, refuses him any financial help. To live, Erba carries out wall decorations and other small works.
Between 1912 and 1913 Erba's research becomes more committed and intense, and in a decisive transformation of perspectives. In 1914 he was one of the founders of the New Trends group with Giulio Ulisse Arata, Leonardo Dudreville, Achille Funi and Giovanni Possamai, participating in the interventionist demonstrations together with the other futurists.
In the imminence of Italy's entry into the war, Erba enlisted with his futurist friends Marinetti, Boccioni, Funi, Sant'Elia, Russolo, Piatti and Sironi, the critic Mario Buggelli and the journalist Renzo Codara of Corriere della Sera, in the Battalion Lombardo Volunteer Cyclists Motorists. On the night of 12 to 13 June 1917, during an attack on the Ortigara, Carlo Erba fell hit by a shrapnel from a grenade.
The body of Carlo Erba was never found, despite the numerous searches carried out after the war was over. Erba will receive the bronze medal in memory of him.