John was the eldest son of the Duke George the Bearded (1471-1539), from his marriage to Barbara Jagiellon (1478-1534), daughter of King Casimir IV of Poland.

Because of the good relationship between his father to the Habsburg family, he was raised in Brussels, together with the future Charles V. John was introduced at an early age to the business of government by his father, but he soon developed a penchant for idleness, and was more interested in good food, alcohol and parties.

Elisabeth leaned towards the Lutheran teachings and soon fell in conflict with her husband and his strict Catholic parents.

[1] Even at John's death bed, his wife and his father disputed religious issues.

He was buried in Meissen Cathedral and succeeded as hereditary prince of Saxony by his younger brother Frederick.