[1][2] Under her leadership, the Center helped win Whole Woman's Health v. Hellerstedt, a U.S. Supreme Court case.

Northup was the founding director of the Democracy Program at the Brennan Center for Justice at NYU School of Law.

From 1989 to 1996, she served as a prosecutor and deputy chief of appeals in the U.S. Attorney's Office for the Southern District of New York.

She served as a law clerk to Alvin B. Rubin of the U.S. Court of Appeals for the Fifth Circuit in New Orleans.

She is married to Jim Johnson, the Corporation Counsel of the City of New York and a former candidate for New Jersey governor.