Caroline von Lengefeld was the oldest child of an aristocratic family in Rudolstadt; she was raised and educated with a younger sister, Charlotte. Though her family belonged to the lower nobility, after her father died the financial situation was somewhat troubled. At 16, Caroline became engaged to Friedrich Wilhelm Ludwig von Beulwitz (1755–1829), a prominent local courtier, through the arrangement of both families. Much of her long engagement was spent with her family in Switzerland, a trip paid for by von Beulwitz; they married shortly after Caroline's return in 1784. Lacking shared interests, the marriage was unhappy from the start.
Caroline's closest confidante in the early years of her marriage was her cousin Wilhelm von Wolzogen, who, in 1785, introduced her and her sister to his friend Schiller, then a young and rather poor Weimar poet. In 1788, Schiller moved to a nearby town to be closer to the Lengefelds, and both Caroline and her sister became closer to him. Caroline felt a strong attraction toward him, though how far she considered taking it has been disputed by scholars. Schiller became engaged to Charlotte in August, 1789, and credited Caroline for bringing them together. In the early 1790s, inspired by her friendship with Schiller and other literary figures in Weimar, Caroline began writing herself; her first substantial work was a dramatic fragment in classical form, Der leukadische Fels, in 1792.