From 1557, James and his brother Ernest Frederick were educated at the court of their guardian, the Lutheran Duke Louis III "the Pious" of Württemberg.

James and his eldest brother Ernest Frederick wanted to be sovereign rulers of their own fragment of Baden.

Their youngest brother George Frederick received Upper Baden, including the Lordships of Rötteln and Badenweiler and the Margraviate of Baden-Sausenburg.

During this period of deep religious division, the Margrave closely watched the three Christian camps: the Catholics, Lutherans and Calvinists.

Afterwards, James converted, like his lead councillor Johann Pistorius had done two years earlier, in the Cistercian monastery Tennenbach on 15 July 1590 to the Roman Catholic faith.

Under the cuius regio, eius religio rule in that treaty, Catholicism was made the state religion of the Margraviate of Baden-Hachberg on 10 August 1590.

The precise Latin language of the autopsy report states that the cause of death was poisoning by arsenic (As2O3).

The events surrounding James III's death illustrate the increasing polarization in religious matters.

The tensions between the faiths had risen very high, and the hunger for power of the German rulers and princelings was very strong.

James married on 6 September 1584 with Elisabeth of Culemborg-Pallandt (born: 1567; died: 8 May 1620), the daughter of Count Floris I of Pallandt-Culemborg (1537–1598 ).