After serving on the University of Chicago Law Review, Professor Trangsrud clerked for Justice Walter Rogosheske of the Minnesota Supreme Court and practiced law with the DC firm of Hogan & Hartson. In 1982, he joined the faculty of the law school, where he has taught civil procedure, federal jurisdiction, remedies, and complex litigation. His writings are primarily in the fields of complex litigation and jurisdiction. 

He was appointed Associate Dean for Academic Affairs in 1993, and Senior Associate Dean for Academic Affairs in 2000; he served in that position until 2006 with the exception of one year as Interim Dean of the Law School in 2004–05. Recently, he co-wrote a new casebook, Complex Litigation and the Adversary System, and a treatise on Complex Litigation: Problems in Advanced Civil Procedure.