Lari served as a professor of literature, philosophy, and theology at seminary of Volterra from 1941 to 1968 and as a professor of letters at the Pontifical Regional Seminary "Pius XII" in Siena from 1955 to 1958.
He was director of the weekly magazine of the Diocese of Volterra, L'Araldo (English: The Herald), from 1953 to 1968 and was the canon of the Cathedral of Volterra from 1948 to 1968.
On 15 October 1968, Pope Paul VI appointed Lari as the Bishop of Aosta, succeeding Mathurin Blanchet. He received his episcopal ordination on 30 November, Bishop Marino Bergonzini acting as the principal consecrator and Bishops Abele Conigli and Carlo Colombo as co-consecrators. He was installed in the diocese on 8 December of that year.
During his episcopate, he welcomed a pastoral visit from Pope John Paul II in 1986 during his vacation in Les Combes. He also visited all the parishes the diocese and repeatedly called for a diocesan synod, which was held from 1988 to 1993.
On 30 December 1994, Pope John Paul II accepted his resignation due to age. He was succeeded as Bishop of Aosta by Giuseppe Anfossi. Lari retired at first to Castelfiorentino and then to the Fabbrica frazione of Peccioli, where he died on 2 February 2007. The funeral was held on 5 February in the Cathedral of Volterra and on 6 February in the Cathedral of Aosta and he was buried in the Aosta Valley town.[1]
