She is foremost known for being the love object of King Gustavus Adolphus of Sweden, and because he wished to marry her prior to his marriage, plans which were however never realized.

Their love affair has been famous in the Swedish romantic history and the subject of fiction, and are documented in their preserved correspondence.

At the royal court, she met King Gustavus Adolphus, who was her second cousin, once removed[1] and they fell in love and wished to marry each other.

The dispute between the dowager queen, the king and Ebba Brahe about the marriage continued until 1615, and has been the subject of romantic plays, stories and poems for centuries.

The king tried to convince his mother with his half-sister Princess Catherine, Duke Henry Julius of Saxony, and chancellor Nils Chesnecopherus with messengers.

During this time, the king himself had an affair with Margareta Slots during his absence in the war, which was to have helped Brahe to make her mind.

The same year, she received a proposal from Count Jacob De la Gardie, which she accepted two years later: 11 November 1617, her engagement was celebrated at the court of Queen Dowager Catherine, and 24 June 1618, Ebba Brahe married Jacob De la Gardie in the presence of the two queen dowagers and the brother of the king in Stockholm.

When Magnus Gabriel lost his position as favorite with the queen in 1653, Ebba Brahe fell upon her knees before the queen to ask him to forgive him, and she also sought the help of Axel Oxenstierna to reinstate him in favor, though she privately blamed the Oxenstierna party for having caused the fall of Magnus Gabriel.

Ebba Brahe actively used her influence over her son to put forward both her own and various supplicants demands, recommendations and suggestions.

A play, Gustav Adolf och Ebba Brahe, was written about Ebba Brahe by Gustav III of Sweden, composed by Johan Henric Kellgren, which was performed in the Gripsholm Castle Theatre in 1785; the play presents her son Magnus Gabriel De la Gardie as the son of the king.