During his graduate studies at Princeton, Reeve also served as a headmaster of a grammar school in nearby Elizabeth, New Jersey, associated with the college.

In 1772 he moved to Litchfield, situated on the crossroads of important inland trade routes, to open a new law practice.

Reeve, while a fervent supporter of the patriot cause, did not enter active service early in the Revolutionary War.

However, in December 1776, the Connecticut Assembly called upon him to travel the state to drum up volunteers for the Continental Army.

In the beginning, Aaron Burr lived upstairs and took instruction in the downstairs parlor, adjacent to the gathering room where Reeve held mock court.

In 1781 Reeve worked with Theodore Sedgwick to represent Elizabeth Freeman (known as Bett), a slave in Sheffield, Massachusetts, in a legal bid for her freedom.

Bett had listened to discussions related to the Sheffield Declaration, and to a reading of the 1780 Massachusetts Constitution, the latter containing the phrase "all men are born free and equal".

Due in part to notoriety gained from the Elizabeth Freeman case, Reeve's student enrollment began to grow.

His home, now known as Tapping Reeve House and Law School, was designated a National Historic Landmark in 1965.