Shine @ The Academy won a competitive pitch for the account, completing the supermarket chain's new agency roster.
The account will be led by CEO Mitchell Kaye and creative director Dan Glover, whose agency The Academy bought a majority stake in Shine at the start of the year.
The agency will report to Morrisons group marketing and customer director Andy Atkinson, and PR director Julian Bailey.
Atkinson said: "After listening hard to customers, Morrisons has a clearly defined brand – we are foodmakers and shopkeepers, which makes us unique. Shine @ The Academy has shown it really understood what this means for our customers and we were impressed by the meaningful ideas it had to bring this alive for our customers and staff."
For the past four years, 3 Monkeys held a combined brand and product PR account for Morrisons, until a review was launched in December with the supermarket saying it would have one agency for product and one for brand.
Cirkle pitched against Stir PR, Lexis and 3 Monkeys to win the product account.