Balthasar was born around 1560 to a wealthy and powerful family, as son of Hungarian captain Andrew Báthory and his wife Margarita Majláth de Szatmár.

Stephen Báthory was not only king of Poland at that time, but earlier, in 1571, was elected Prince of Transylvania, which did not give up title even after leaving for Kraków.

Hoping that his family be consolidated into the power, and that the infant reached an older age to govern, Stephen continued to reign until his death in 1586.

Later he joined the opposition of Sándor Kendi (his father-in-law), who refused to attack the Turks, but aimed to reach an amicable solution to the conflict.

In August of that same year, Sigismund regained power, and imprisoned all noble opponents including cousin Balthasar, who was later strangled in his cell.