Taylor will move to the supermarket chain in April as group director of corporate affairs. The newly created role oversees government relations and corporate responsibility issues and reports to marketing and comms director Angus McIver.
Taylor joined Portland PR in 2004 after three years as a special adviser to former defence secretary Geoff Hoon.
He has also worked in the Labour Party's policy unit and as an adviser to the director general of the Confederation of British Industry.
Bradford-based Morrisons recently hired Lexis PR to a consumer and corporate PR brief (PRWeek, 7 March).
The supermarket chain has reported a growing market share for the second successive quarter while Tesco's share has dipped, according to figures by TNS World-panel.
Morrisons has enjoyed a change in fortunes since undergoing a £450m brand makeover last year.
This week it emerged that founder Ken Morrison was stepping down.
Citigate Dewe Rogerson is retained by Morrisons for financial PR.