Aggarwal's appointment is the fourth since February 2014 after the then CMD Chandraprasad retired from service.
He took the additional charge from P J Joseph, CMD of Agriculture Insurance Corporation, a week ago, industry sources said today.
After Prasad's retirement, NIC Director and General Manager A V Girija Kumar served as the acting Chief for a year.
However, he was later transferred to Chennai-based United India Insurance as General Manager.
The UPA government had conducted the interview to select a CMD for the company and shortlisted the candidate too but the NDA government is yet to finalise the name, according to sources.