After obtaining a BA in economics from the University of Chicago in 1986 and a JD from Harvard Law School in 1990, Bernstein served as a clerk for the US District Court for the District of Massachusetts and was a visiting research fellow in law and economics at Harvard Law School. She began teaching at Boston University in 1991, and after visiting at the University of Pennsylvania and the Georgetown Law Center, joined the Georgetown faculty in 1995. After visiting the Law School in the fall of 1997 and Columbia Law School in the spring of 1998, Bernstein joined the Law School faculty. She has also been a visiting professor of law at Hebrew University, Tel Aviv University, The College of Law and Business in Ramat Gan, and the Interdisciplinary Center in Israel. Bernstein was recently appointed as an international research fellow at the Oxford University Center for Corporate Reputation.

Bernstein's research interests are in the area of contracts and commercial law with a special emphasis on industry specific dispute resolution, modern supply chain relationships, social network analysis, and the intersection of strategy and relational contracting. She is also interested in the design of commercial courts in emerging and transitioning economies and the relationship between social structures and economic development.