David Fischel has been at the helm since 2001 and with the company since 1985. The 60-year-old will stay in the post and on the board until a successor has been found.
Details of the departure come three months after Hammerson ditched a £3.4 billion takeover of the Lakeside shopping centre landlord.
The deal was thrown into turmoil when France’s Klépierre made two approaches for Hammerson at 615p and 635p before abandoning talks.
Fischel had been expecting to stand down when the Intu-Hammerson deal completed.