Montrose previously worked for Octopus Group as head of design between 2016 and 2018, on Vodafone, Adecco Group and the British Heart Foundation, among other accounts.
In the past two years he has worked in digital design roles on enterprise-scale digital platforms for FTSE100 companies including Sage, easyJet, Toyota and Taylor Wimpey.
Octopus Group chief executive Jon Lonsdale said: "With our creative reputation growing in the industry, it's important to invest in coming up with the best digital content to drive our client campaigns. Dave gets the DNA of this company and the ambition of what we're trying to achieve."
Octopus Group was one of the big winners at the 2019 PRWeek UK Awards, picking up three awards with Hectare Agritech for the 'Tudder' campaign.