This dissertation examines political life at the Swedish Gustavian Court through Duchess Charlotte (1759–1818). She was the Swedish monarch’s sister-in-law and well-known for her political memoirs. This study reassesses the Duchess as a political agent in her own right by taking into account earlier neglected sources. Drawing inspiration from previous research, I elaborate my empirical findings in an analytical framework called court politics. My claim is that politics involved both men and women at court since it was a key part of social life. I also structure the political agency of the Duchess into six different spheres. Each sphere is equivalent to a combined set of space, social relations, and activities, each of which supplied her with political capital. There are four spheres corresponding to the essential features of the royal identity: firstly, being at the head of a court; secondly, as part of the Swedish royal family; thirdly, in the performance of social duties at court; and fourthly, being the Duke’s consort. The two other spheres derive from the Duchess’s personal life, such as in her relationship with the Fersen family and her close circle of female friends. My examples reveal the Duchess acting as a leading figure in the social life of the Stockholm elite, hereby influencing the composition of political circles. She acted as a patron for court positions and solicited the Duke and the monarch for political purposes. When she was unsatisfied with their political decisions, she refused to host any social occasions, creating disorder within court society. The major focus in previous investigations of elite women’s political power has been on their marital status as a means of influence. By framing the Duchess’s agency in six spheres, I position her between the aristocracy and royal authority, together with both men and women of her social status. Thus, this case study offers a display of the complex dynamics of power at the Gustavian court.