Born the child of the painter Karel van Mander, she was a part of one of the two native theatre troupes created when public theatrical activity became legal in Denmark in 1746, following a ban.

The organist Carl August Thielo was the first to be given a theatre privilege, and he opened a theatre at Store Kongensgade in 1747; the same year, Julius Henrik von Qvoten opened one which played in both Danish and German, and Lenkiewitz is believed to have been a part of the Qvoten-troupe.

Together with the other members of these troupes, Lenkiewitz belonged to Denmark's first wave of 'native' actors, and together with her female colleagues of 1747, such as Anna Dorothea Lund and Caroline Thielo she was also her country's first professional actress; during the 18th century, the theatre of Copenhagen was short of actresses because of the bad reputation of the profession; in 1753, there were only five in employment in Denmark.

As she was the eldest of the actresses, she was also given many supporting parts as elder females in plays, which were numerous; in 1752, she was recognized for her great professionalism and usefulness.

Her last ever parts were the leading roles of Flaminia in Den coquette Enke, and Duraminte in Hver Mands Ven, in the 1769–70 season.