FRANKFURT — Weighing in on an issue that revived questions about the role of German business in World War II, a historian has partly confirmed and partly refuted reports that a well-known consultant falsely portrayed his father as a Nazi resister when in fact he was head bookkeeper for the Hitler Youth.

Roland Berger suffered significant damage to his image as consigliere to chancellors and to chief executives after The New York Times and other news media outlets reported last year that he had constructed a legend about his father that was at best incomplete.

Mr. Berger, who was a child during the war, defended himself by saying that he had believed the stories his father told him. He hired Michael Wolffsohn, author of numerous books on German and Jewish history, to investigate. Mr. Wolffsohn’s report, which was published online on Sunday, made it clear that Mr. Berger’s father was no war criminal but also not the hero whom his son had often portrayed.

Georg Berger, the father, was an early member of the Nazi party who profited from the regime and had held several influential jobs, including a high-ranking post at the Hitler Youth. But he later fell out of favor and suffered Nazi injustice, including several months in a Gestapo jail, according to Mr. Wolffsohn.