Bartholomew Dandridge practiced law and managed plantation property in Virginia before becoming a participant in the creation of the independent state. Law, inheritance, and marriages placed him among New Kent's wealthy landowners. His household and estates relied on enslaved workers. He was Martha Washington's younger brother, but his political and judicial career was distinct from that of his son, also named Bartholomew, who served as Washington's secretary.

Elected to the House of Burgesses in 1772 and 1774, Dandridge worked on committees dealing with elections, grievances, and courts. He represented New Kent in all five Virginia Revolutionary Conventions between 1774 and 1776. As conflict with the royal government intensified, he helped consider disputes over the governor's removal of gunpowder and questions concerning the legitimacy of elections.

In May 1776 Dandridge proposed a resolution ending allegiance to Britain. His proposal and related drafts contributed to the convention's instructions that Virginia's Continental Congress delegates move for independence. He also served on the committee preparing Virginia's Declaration of Rights and constitution. Chosen for the Council of State in June, he helped advise the governor as the new government organized administration and supplied wartime forces. After resigning early in 1778, he briefly returned to the House of Delegates and chaired its trade committee.

The legislature elected Dandridge to the General Court in May 1778. That office subsequently entitled him to sit on the Court of Appeals. In Commonwealth v. Caton in 1782, colleagues discussed whether judges could invalidate legislation contrary to the constitution; Dandridge declined to decide that broader question. He also managed land and Custis estate responsibilities. He remained on the bench until his death in 1785. His career joined colonial legal practice, revolutionary constitution making, and the development of Virginia's courts.