In 1876 he earned his medical degree in Paris, and in 1882 became chief obstetrician at the Hôpital de la Charité.
In 1895 he succeeded Étienne Stéphane Tarnier (1828–1897) as chair of obstetrics at the Hôpital Maternité.
Pierre Budin was a founder of modern perinatal medicine, and made many contributions in efforts to reduce infant mortality.
He stressed the importance of proper nutrition and prevention of infectious disease in newborns, as well as education of new mothers on these subjects.
He also popularized a technique known as gavage for feeding premature infants who were too weak to receive nourishment by conventional methods.