Christian Friedrich Schwartz (1726–1798), a theologian of the Protestant-Lutheran denomination educated in Halle, was an eminent missionary of the Danish-Halle Mission. He lived and worked among the Tamils in South India for 48 years, earning the respect and trust of the people across religious boundaries. It is evident that he left a significant legacy in the areas of diplomacy, interfaith understanding and social development. Schwartz became a confidant of the Hindu King of Tanjore, Tulaji (1738–1787), who appointed Schwartz as the guardian of his son and later King Serfojee II (1777–1832). He was an advocate of education, science and social justice and campaigned for the rights of the peasants and founded schools and medical institutions. His theological convictions, influenced by Halle Pietism, frequently resulted in practical measures, such as the establishment of a civil court in Tanjore or the immunization of the population against smallpox. This biography provides a new perspective on Schwartz’s life. The focus of the study is not on European interests in and outside India, but rather on his personality and tangible work on the ground. Based on a variety of sources in Halle, Copenhagen, London and Oxford as well as his Tamil writings, a fresh perspective on the man and his work is offered.