She worked as a legislative assistant to Senator Harrison A. Williams (D–NJ), and subsequently for United States Congressman Jonathan B. Bingham (D–NY).

Kessler worked for the New York City Board of Education, and then opened a public interest law firm.

[2] In 2002 she heard a case lodged by the Holy Land Foundation for Relief and Development appealing against their designation as a terrorist organisation under Executive Order 13224.

He also stated that, "This is the first time the judicial branch has exercised its inherent power to control the excesses of the executive as to treatment of prisoners at Guantanamo Bay.

"[4] Kessler twice denied relief to detainee Jihad Ahmed Mustafa Dhiab, first determining that she had no jurisdiction over his confinement conditions, and, after that theory was rejected by the United States Court of Appeals for the District of Columbia Circuit, that the government was permitted to use force-feedings on detainees during the Guantanamo Bay hunger strikes.