She entered the service of Charles I de Lalaing, Governor of Oudenaarde and Seigneur of Montigny.

The young Emperor Charles V met the beautiful Johanna when he visited the castle of the Seigneur of Montigny in autumn 1521.

Their short affair produced a daughter who was named Margaret and put in the care of the De Douvrin family in Brussels.

The Emperor granted Johanna van der Gheynst a modest pension.

On 13 October 1525 she married Jean van den Dyke, a jurist and member of the Brabant Chamber of Accounts.