He was a posthumous child as his father, Wacław II, died a few months before the birth of his son. In early childhood he was in the care of his grandfather, Prince Kazimierz. After Kazimierz's death, and according to his ruling, the Bohemian magnate, John of Pernątejn, assumed care of the child, in exchange for assurances that the young prince would marry Pernątejn's daughter, Maria. Wacław spent much time at the imperial court in Vienna up until 1540. On 10 February of that year he married Maria, in accordance with his grandfather, Prince Kazimierz's, will. Three children were born to Wacław and Maria; a son Fryderyk, and two daughters; Anna and Zofia. Maria of Pernątejn was an advocate of Lutheranism in the Duchy of Cieszyn – as her father probably was – although it would seem that John of Pernątejn's role in promoting the new creed is somewhat exaggerated.
      After Maria's death Wacław III was married again, this time on 25 November 1567 to Katarzyna Sydonia (* c.1550 + June/July 1594), the daughter of the Prince of Saxony, Franz I. Three sons were born of this union; Chrystian August, Adam Wacław and Jan Albrecht, and three daughters; Maria Sydonia, Anna Sybilla and a third who died, unnamed, in infancy. After her husband's death Katarzyna Sydonia acted as regent for her juvenile son, Adam Wacław. She supported the Reformation in the Duchy of Cieszyn. In the year her son reached the age of majority she married the district commander of Trenčin, Emeryk Forgach. She was buried in the convent in Lubiąż.
      During Wacław III Adam's rule the Duchy of Cieszyn experienced a period of stability, even though financing the wars with the Turks and the necessity of building defensive entrenchments in Jablunkov represented significant expenses. They were built in order to repel a possible attack on Silesia by the Turks. In 1573 he was an unsuccessful candidate for the Polish throne.
It is not true, as is often claimed in the literature, that the Reformation was well established during the tutelary rule of John of Pernątejn in the Duchy of Cieszyn. Up until 1540 Catholic priests carried out their duties unmolested (also at the princely court). In fact the Reformation began after that date and its most conspicuous in the case of Cieszyn was the dissolution of the Bernardine and Dominican monasteries, and then in the Duchy of Cieszyn a little later the dissolution of the Benedictine monastery in Orlova.

(K. Jasiński, Rodowód, pp. 197-199, M. Kasperlik, Herzog Wenzel, passim, I. Panic, Wybrane zagadnienia, pp. 7-11)