John Wolff, 99, a Georgetown University faculty member believed to be the oldest active law professor in the country, died of cardiovascular disease Dec. 7 at his home in Washington.

Mr. Wolff, who had taught at Georgetown's Law Center since 1961, was most recently an adjunct faculty member. He taught a comparative law class in the fall semester, which ended a few days before his death.

Georgetown's new international and comparative law library is named for him.

He was born in Montreal and raised in Berlin and studied law at universities in Berlin and Heidelberg. He received a law degree from the University of Heidelberg in 1929. That same year, he went to New York, where he received an advanced law degree from Columbia University in 1930 and became a member of the Columbia Law School faculty.

In 1932, Mr. Wolff returned to Germany to pursue a legal career, but a year later, when the Nazi government came to power, he fled Germany, returned to New York and resumed teaching law at Columbia.

During World War II, Mr. Wolff enlisted as a private in the U.S. Army, rising to the rank of lieutenant colonel in the Judge Advocate General's Corps. After the war, he served as deputy to the U.S. representative to the United Nations War Crimes Commission, which prepared him to later teach Georgetown's first class on international human rights.

Upon returning to the United States, Mr. Wolff worked for the Department of Justice, retiring in the 1970s but continuing to serve as an adviser on international and foreign law.

He taught classes in international civil law and comparative law and an introduction to U.S. legal methods for foreign lawyers. He was a recipient of Georgetown's Vicennial Medal in 1981 for distinguished service, the Charles Fahy Distinguished Adjunct Professor Award in 2001 and a Certificate of Appreciation in 2003 for his 42 years of service to the school.

In addition to teaching, Mr. Wolff published articles in American and German legal publications and served as deputy chairman of the Council on International Law of the Federal Bar Association.

A lover of classical music and world affairs, Mr. Wolff was an avid violinist and a strong supporter of the Democratic Party. He was a founding member of the Department of Agriculture Symphony Orchestra, and he also played with other orchestras and chamber groups, focusing his attention on the works of Haydn and Mozart.

His wife of 57 years, Eleanor Miltimore Wolff, died in 2002. A son, John Wolff, died in 1973.

Survivors include two daughters, Patricia Hartman of Rockville and Maggie Dunn of Chicago; a brother; four grandchildren; and two great-grandchildren.

John Wolff was believed to be the oldest active law professor in the United States.