Carl Christoffer Gjörwell called her "as beautiful as a spring day" and noted: "Our new M.lle Slottsberg will become one of the greatest dancers in Europe, and never set foot in the theatre without the most constant applause from the Royal box.

Among the parts she danced was Aurora in the Procris och Cephal by Grétry with Carl Stenborg and Lovisa Augusti the season of 1777–78, Lucile in the pantomime ballet La Rosiére de Salency by Jean Marcadet with Antoine Bournonville and Carlo Uttini (1786–87), as Bellona opposite Giovanna Bassi as Pallas in the ballet made by Louis Gallodier to the opera Gustav Adolf och Ebba Brahe by Gustav III (1787–88).

Charlotte Slottberg was widely regarded as a high class courtesan in parallel to her career in the ballet, and she is known to have several rich lovers from whom she benefited financially.

[1] Among her other known lovers were the statesmen count Fredrik Sparre and Carl Wilhelm Seele and several other men from the aristocracy and political and diplomatic world.

Their affair continued on an on-an-off basis for about twenty years, was regarded a scandal and attracted much negative publicity to Duke Charles.

In parallel to her, Duke Charles had a string of other lovers simultaneously - his affairs to Charlotte Eckerman and Françoise-Éléonore Villain, among others, all took place when Slottsberg was his mistress.

In 1790, she was rumoured to have been given an allowance from king Gustav III of Sweden in exchange for influencing his brother Charles to his advantage,[3] which was commented to in a letter by Charles' sister, princess Sophia Albertina of Sweden on 13 April 1790: "He is truly so blinded and enchanted by that nasty Slottsberg, who makes him do all these stupid things and controls him: she is herself bought by the king, who provides her with a pension and inform her of everything, which he wants the duke to do.

"[1] The dislike of the alleged influence of Slottsberg became more intense during Charles' reign as regent during the minority of his nephew king Gustav IV Adolf of Sweden in 1792–96.

[1] When silk and coffee was (temporarily) banned in an extremely disliked sumptuary law by the regency government, the public opinion pointed to the disregard for this law among the upper classes and "In Stockholm it was loudly said, that as long as the mamsell's Slottsberg and Löf (the mistresses of the duke) wore silk and all kinds of finery, such things should not be banned.

[5] This created a scandal and widespread dislike at court, voiced by the duchess, which caused the regent Duke Charles to see a need to make his relationship with Slottsberg less visible, he stopped allowing her to use this type of a carriage and drivers with his ducal livery.

Privately, Slottsberg was in love with the cavalry rider Adolf Fredrik Heitmüller, who reportedly pawned the jewelry given to her by Duke Charles.

[6] After her death, her former lover Duke Charles confiscated her fortune despite the protests of her widower and her surviving mother, claiming that she had debts to him which amounted to the value of her entire estate.