Dawn Elizabeth Johnsen (born August 14, 1961) is an American lawyer and the Walter W. Foskett Professor of Constitutional law, who is currently on the faculty at Maurer School of Law at Indiana University in Bloomington, Indiana. She worked at the Office of Legal Counsel in the United States Department of Justice from 1993 to 1998 and served as acting Assistant Attorney General from 1997 to 1998; she was twice nominated to the post in the Obama Administration. Johnsen's first nomination was approved by the Senate Judiciary Committee in March 2009 in a party line vote, but was not acted on by the full Senate before it recessed at the end of 2009. Obama then renominated her to the post on January 20, 2010 but on April 9, 2010, Johnsen withdrew her name from consideration.
Born in Manhasset, New York, Johnsen attended Carle Place High School in Carle Place, New York, graduating in 1979 as its salutatorian. She received her B.A. summa cum laude in economics and political science at Yale College in 1983 and her J.D. at Yale Law School in 1986, where she served as an Articles Editor of the Yale Law Journal.
After graduating law school, Johnsen clerked for United States Appeals Court Judge Richard Dickson Cudahy of the United States Court of Appeals for the Seventh Circuit from September 1986 until August 1987.