He was the eldest son of Duke Wenceslaus I of Zator by his wife Maria, daughter of Urban Kopczowski, a noblemen from the Duchy of Siewierz.

In 1474, under the pressures of his brothers, Casimir II agreed to make the division of the Duchy in two parts: The natural frontier between the lands was the Sakwa River but with the common rule over the capital and use of the Zator castle.

Casimir II died in 1490 (although the exact date is unknown, but ranked in sources between 8 January and 7 July) and was buried in the Mary's Church of Kraków, which was financially assisted by him.

Under the terms of the treaty of 1477, his lands were inherited by his brother Jan V, who reunited all the Duchy of Zator under his rule.

Around 12 August 1482, Casimir II married with Margareta (also known as Machna; d. 4 January/28 July 1508), daughter of Duke Nicholas V of Karniów.