Berthold IV succeeded his father, Conrad I, in 1152 as Duke of Zähringen.

[2] This interfered with Berthold's claims and Berthold was given the title of Rector of Burgundy and was made overlord over the Transjuran ("Swiss") parts of Burgundy, Geneva, Lausanne and Sion.

The rivalry with Duke Frederick IV of neighbouring Swabia caused him to fight on the side of Welf VI in the Feud of Tübingen (1164–1166).

An entry in the necrology of the Abbey of Saint Peter in the Black Forest reads Berchtoldus 4. dux de Zaeringen, officium cum 5 candelis.

Depositio Iohannis Tüfer abbatis: "Berthold IV, Duke of Zähringen donated 5 candles for the memory of John the Baptist".