After the American Revolution began, her own Patriot leanings led her to offer the use of her house, the Hermitage, as a meeting- and resting-place for revolutionaries, including Alexander Hamilton, Marquis de Lafayette, and Aaron Burr; it was briefly used as the headquarters of George Washington, who counted her amongst his friends.

The couple moved to New York City due to Burr's legal practice, and she acted as a crucial ally as he began his political career.

[3] At the age of seventeen, Theodosia married Jacques Marcus Prevost (1736–1781), a Swiss native and the brother of Augustine Prévost (1723–1786), who was serving as commander of the British Army forces in New Jersey.

[4] Despite her family's background (both her stepfather and husband were officers of the Royal American Regiment) Theodosia aligned herself with the Patriots,[3] counting William Livingston and Robert Troup as friends and allies.

[7] During the war, with her estate being owned by her husband, it was at various times under risk of confiscation as Loyalist property; her powerful friends, allies and patrons, including Livingston and William Paterson, ensured the case was halted.

[10] Theodosia and Burr's writings to each other covered politics, philosophy and feminism, with the two discussing both Rousseau and British feminist Mary Wollstonecraft.

This increase in work led to him travelling more, but their "intellectual partnership" did not suffer: the two wrote letters back and forth notable for their candor, with Theodosia constantly disagreeing with her husband's views, "never shy to point out his flaws", and Aaron treating her as he would any other intelligent person, sending her political books and newspapers on a regular basis that he thought she would enjoy.

[13] Theodosia's keen sense of observation and adeptness at "judging [Aaron's] peers on the national scene" made her a crucial ally in his political career, particularly after he joined the United States Senate in 1791.