[2] He is known for his studies of American criminal procedure and the Fourth Amendment to the United States Constitution, as well as computer crime law and internet surveillance.

From 1998 to 2001, he was a trial attorney in the Computer Crime and Intellectual Property Section of the U.S. Department of Justice's Criminal Division.

[6] In 2003, Kerr took a leave of absence from the law school to clerk for Justice Anthony M. Kennedy of the United States Supreme Court during October Term 2003.

Kerr was repeatedly cited in the Ninth Circuit's 2008 opinion Quon v. Arch Wireless Operating Co., Inc.,[11][12] which held that users have a reasonable expectation of privacy in the content of text messages and e-mails.

[13] In response to a 2011 comment by Chief Justice John Roberts criticizing the irrelevancy of legal scholarship for focusing on issues such as Immanuel Kant's influence on 18th century evidentiary approaches in Bulgaria, Kerr wrote a short, humorous paper on the topic in 2015, finding that such influence was highly improbable.