Narasimhan was formerly executive director of HUL.
Mohit Burman takes over as non-executive chairman of the company.
HUL becomes the first Rs 50,000 crore FMCG company after posting a 5 per cent surge in Q4 profit.
Harpic Power Plus 10X Max Clean led the brands' list.
The agency is tasked to craft creative strategies for the ITC brand.