During World War I he openly denounced the Armenian genocide through press articles and interviews and he didn't hesitate to describe the horror the Turkish rulers perpetrated against the Armenians. He said if everyone had seen what he had, the condemnation of those acts would have been universal especially on the side of the Christian powers. He was in touch with American Ambassador Morgenthau and the Vatican's Angelo Dolci, and this way he managed to save 50,000 Armenians from deportation and mass murder.
In 1886 he became the first director of the Italian Foreign Minister Archives. In the years 1911-1915 he served as Italian Consul in the provinces of Trabzon, Erzurum, Van, Bitlis, and Sivas. He was eyewitness to the massacres perpetrated by the Young Turks. He had to leave his office in August 1915, when Italy declared war on Turkey. His interview by, il Messaggero, called for, "il più risoluta riprovazione e la vendetta dell'intera Cristianità"(forceful condemnation and vengeance by the whole of Christendom).
From 1918 to 1920 he was the only Western Ambassador to the Republic of Ararat. He then tried to obtain the intervention of two Italian warships in favor of the Armenians, but the newly appointed Italian Foreign Minister prevented him from doing so.
In 1920 Gorrini took a stance in favor of the Italian support to the independence of Armenia in a Memorandum attached to the Treaty of Sèvres. There he wrote: "If we don't solve the problem of Armenia, even partially, peace will be periodically disturbed throughout the world". In the following 20 years he helped many Armenians to flee Turkey heading to Italy. He also personally rescued an Armenian girl who would stay with him till his death. In 1940 Giacomo Gorrini published a book in which he stated that the Armenians should regain the land they had lost as soon as possible. This would include Kars, Van, Ardahan and others.
- Symbolism, Violence and the Destruction of Religious Communities in the Russian and Ottoman Empires c.1870-1923, Cathie Carmichael, Can Faiths Make Peace?: Holy Wars and the Resolution of Religious Conflicts, ed. Philip Broadhead, Damien Keown, (I.B. Tauris, 2007), 77.
- Gorrini on Gardens of the Righteous Worldwide - Gariwo
- Giacomo Gorrini in the Italian State Archives