Arnold joins Rise from Ipsos Mori, where he was head of the marketing sciences function. Prior to that Arnold worked for Dunnhumby and 2CV: Research.
In his new role, starting on December 1, Arnold will work across Rise's client base and be at the centre of the agency's approach to integrated communications.
Mark Bauer, Rise Communications partner, said: "Data analysis has always been important aspect of our offering, and supports our fact-driven creativity approach to helping our clients 'Profit more from communications'.
"Creating the head of data strategy role enables us to build on our already strong capabilities in this area."
Arnold said: "I am greatly looking forward to developing further the data strategy function to offer imaginative and focused quantitative solutions, insight and strategic consultancy."
Rise Communications formed in 2003 and became part of the Eden State Group in 2007 following £10m worth of funding from Ingenious Media Active Capital.