Raja will be replacing James Lenton in the role, who gave notice of his resignation to the company in January 2020.
He will start his new position as CFO and executive director on 26 April 2021.
Previously, Raja has served as CFO at G4S plc, Misys plc and Logica plc.
Rita-Rose Gagné, chief executive of Hammerson, said: “Himanshu is an experienced CFO who brings a blend of strong financial, strategic and leadership qualities.
“On behalf of the Board, and all colleagues I look forward to welcoming him to the Company and benefitting from his insight and experience.”
On his appointment, Raja said: “I am excited to be joining Hammerson during this period of unprecedented change in the sector and look forward to supporting Rita-Rose as she leads on the strategic review of the business to create value going forwards”