Aldo Mei was born in Ruota, a hamlet of Capannori, on 3 March 1912. He entered the seminary at the age of 14 and was ordained a priest in 1935. He became parish priest of Fiano, a village in the town of Pescaglia. With the outbreak of the war, he formed relations with Father Arturo Paoli and the Oblates of the Holy Face, a community of young priests who provided assistance to war victims and those persecuted by the fascists.

Father Aldo Mei acted in the first person: he helped and gave protection to displaced persons, Jews, anti-fascists, Allied soldiers who escaped from prison camps, draft dodgers. It also helped to provide food and support to partisans acting in the surrounding area. He was arrested by the Germans on 2 August 1944 shortly after celebrating mass. He was transferred to the Pia Casa in Via Santa Chiara in Lucca together with thirty other civilians arrested during the same roundup. There he was subjected to a summary trial and sentenced to death on charges of hiding and giving protection to a Jew, administering the sacraments to partisans and owning a radio. Before his execution, he wrote four letters (addressed to family members, his brother, his friend Adolfo and various acquaintances), in which he stated: "I am dying first of all for a reason of charity - for protecting and hiding a very dear young man." Despite attempts by Monsignor Torrini, archbishop of Lucca, to intercede for him, on the evening of 4 August 1944 he was led on foot outside the Medici walls near Porta Elisa in Lucca and was forced to dig his own grave, before being shot by a Wehrmacht platoon. His body was later exhumed and moved to the Barbantine nuns of Lucca in Via Elisa.

On 4 August 1945, the first anniversary of his death, a monument in his memory was erected at the execution site. Father Aldo Mei was awarded the Silver Medal of Military Valour on 30 July 1977. His body was moved on 31 October 1987 and interred in the church of San Pietro Apostolo di Fiano (Pescaglia), after a solemn ceremony widely attended by the authorities and the community. His bloodied shirt, hat and glasses are displayed there in a glass case, while a monument in his honour has been erected outside. The Sentiero della Memoria e della Pace (Remembrance and Peace Route) that leads from the hamlet of Fiano (Pescaglia) to Monte Acuto was named after him. A number of towns in Lucca and Tuscany have named a street after him.