He replaces Troels Oerting who left the bank in November.
McNulty, who spent 17 years at JPMorgan after working in Hong Kong and Britain’s police forces, will join Barclays in May according to the memo seen by Reuters.
A spokeswoman for Barclays confirmed the appointment.
The hire comes as Barclays steps up its efforts to combat the threat of cyber crime, having launched a new joint operations centre at its headquarters in London’s Canary Wharf district.
The unit is designed to centralise the bank’s efforts to detect and combat cyber threats.
(Refiles to clarify memo seen on Wednesday)
Reporting By Lawrence White; Editing by Susan Fenton