But Government Department Chair Roderick MacFarquhar said he regarded the complaint as misguided.
"I was and am a friend of Peter's and I have had off dealings with him and I'm sorry he feels he has to take this step," said MacFarquhar, who is also Williams professor of history and political science.
The lawsuit follows over two years of internal appeals to the denial of Berkowitz's tenure in 1997.
In 1996, a government department committee recommended that the university tenure Berkowitz. But President Neil L. Rudenstine denied the junior professor tenure after considering the recommendations of an ad hoc committee.
Berkowitz claims "bias and conflict of interest" on the part of several ad hoc committee members made the review process unfair and violated Harvard's own internal guidelines.
A Middlesex County Court clerk said it will likely be several years before a trial is held. Berkowitz has requested that a jury hear the case.
Harvard must file an answer to Berkowitz's complaint within 20 days.
Berkowitz, whose most recent book is Virtue and the Making of Modern Liberalism, is now a professor at George Mason University Law School in Arlington, Va.