The revelation was made by David Pickens, who is currently the chief of staff to the president of the Chicago Board of Education.
Pickens said he himself maintained the list, which was created simply as a way to keep track of all of the calls the office received. The existence of such a list had not previously been revealed.
The report doesn't imply any wrongdoing on the part of Duncan, who is now the U.S. Education Secretary, but does raise further questions as to what he knew about the practice and when he knew it.
The district's inspector general and federal authorities are investigating whether there was any bribery, corruption or fraud happening in conjunction with requests for admission to the elite schools, the Tribune explains.
Last year, the newspaper's investigative reporting revealed that such practices were occurring at the University of Illinois. After the revelations, Gov Pat Quinn appointed an independent Admissions Review Commission, which eventually recommended that all appointed board trustees resign.
A call to Chicago Public Schools on Monday evening was not returned.