Daughter to Count Conrad Reventlow (1644-1708) and Anna Margrethe Gabel (1651-78), she married Count Niels Friis (1665-1699) in 1688 and statesman count Ulrik Adolph Holstien in 1700, and belonged to the highest aristocracy in Denmark. In 1707, she was granted Seekamp in Slesvig as her own fief by her father.
From 1712, the king had a relationship with her half-sister, Anna Sophie Reventlow, and later, he married her. Holstein had a large influence over her sister and her royal brother-in-law and was called “madame la grande chancellière” (Madame Chancellor), and her views went through her sister to the king and to the government, thereby making her an important politician in the 1710s and 1720s. She held a salon in her Palace in Copenhagen, and it was well known by foreign ambassadors that she was one of the greatest powerholders during the reign of Frederick IV of Denmark and that it was important to have her liking.
In 1730, Fredrick IV died and his son banned Anne Sophie Reventlow from court and fired Holstein's husband. Holstein lost all power and spent the rest of her life with her family.