Though Tannery's career was in the tobacco industry, he devoted his evenings and his life to the study of mathematicians and mathematical development.
Tannery's life of public service began as he then entered the École d'Applications des Tabacs as an apprentice engineer.
Biographies of Tannery describe him as an ardent patriot and claim that he never fully accepted the humiliating Treaty of Frankfurt.
After the war, his interest in mathematics continued, and Comte's ideas would influence his approach to the study of the history of science.
Tannery moved several times with his career in the tobacco industry: to Périgord in 1872, to Bordeaux in 1874, to Le Havre in 1877, and to Paris in 1883.
His wife, Marie, would survive until 1945, and she published several of his works posthumously, helping to ensure that his legacy would live on.