Born in 1830. Giacomo Grillo began his career in 1853 as an employee of the Banca Nazionale, the Kingdom of Sardinia's issuing bank, which had its head office in Genoa. Shortly afterwards he was appointed Secretary General and chief assistant to the Director General, Carlo Bombrini. When Bombrini died in 1882, he took over the running of the bank, which had by then moved to Rome.

He was the first Director General of the Bank of Italy after it was created from the merger of the Banca Nazionale and the two Tuscan banks. He held the post for little over a month, from January until his resignation on 24 February 1894. Died in 1895.