Lars Olof Jonathan, also known as Nathan, was born into the family of a Lutheran priest. He studied ancient languages and Arabic, as well as theology and the history of religion. He married one of the university’s 20 female students and later had 13 children with her. After being ordained as a priest he became the pastor of the Swedish community in Paris (1894—1901) whose famous members included Alfred Nobel and August Strindberg. He continued his studies and obtained his doctorate in theology at the Sorbonne. His stay in France reinforced his liberal approach to theology, and his work for the community convinced him that action was as important as faith.

In 1901 he became a professor of theology at Uppsala and in 1912 he became a professor of the history of religion at Leipzig university. This academic period enabled him to write a number of books on the history, psychology and philosophy of religion. His work laid a foundation for the comparative study of religions.
In 1914 he was appointed Archbishop of Uppsala and the leader of Sweden’s Lutheran Church.

He was internationally renowned as a pioneer of the ecumenical movement of 20th century. In 1925 Soederblom organised a Christian conference attended by representatives of the Anglican, Protestant and Orthodox churches. The attendees emphasized the need to reconcile subjective spirituality and objective social activities and were united in their joint appeal for world peace. The conference was the cornerstone for the establishment of the World Council of Churches in 1945.