In spite of a degree in law awarded him in 1795 by the University of Pisa, Gazzeri never undertook a legal career, preferring to study the natural sciences. In 1807 he was appointed to the Chair of Chemistry at the Secondary School of Physical and Natural Sciences in Florence, his native city. Under the Napoleonic government he conducted numerous research projects in pharmaceutical and applied chemistry, promoting the industrial development of the country and, after the Restoration, was appointed by Ferdinand III of Hapsburg to the Chair of Chemistry at the School of Pharmacology of the Santa Maria Nuova Hospital, where he taught for almost forty years. It was during this period that Gazzeri published his Compendio d'un trattato elementare di chimica [Compendium of an elementary treatise on chemistry] (1819), a work consisting of one hundred lessons clearly influenced by the modern theories of French chemists. Appointed General Commissioner of the Ironworks and Mines of Tuscany in 1822, he proposed that drilling be carried out in Larderello area for the purpose of activating new soffioni. He also worked assiduously in the field of agricultural chemistry, publishing numerous memorandums of scientific nature for the Accademia dei Georgofili.