Elisabeth was born in Wolfenbüttel, the daughter of Duke Henry Julius of Brunswick-Wolfenbüttel (1564–1613) from his second marriage with Elizabeth (1573–1625), eldest daughter of King Frederick II of Denmark.

Elisabeth married first on 1 January 1612 in Dresden, to Duke August of Saxony (1589–1615), the administrator of the diocese of Naumburg.

August suddenly died at the age of 26, after only three years of marriage.

Elisabeth's second husband was John Philip of Saxe-Altenburg (1597–1639).

[1] The motto of the Duchess, who was with both an Albertine and an Ernestine,[2] was: All my delight is in God.