The brief includes managing the brand’s press office for trade, specialist and consumer media as well as its social media channels.
The agency will promote Saucony’s sponsored events throughout 2015, including the Cambridge Half Marathon, Brighton Marathon and London Marathon Expo.
Brandnation will also be responsible for the launch of Saucony’s multichannel marketing campaign for its SS15 product launch.
Brandnation MD, Mary Killingworth, said: "Working with the marketing team at Saucony we have ambitious plans to engage a wider mass audience while maintaining the core identity, credibility and heritage of the brand."
Emma Roach, Saucony marketing manager for UK and Ireland, said: "Our brand has always had a very credible, loyal and knowledgeable customer base, and with the help of Brandnation we hope to communicate our stylish, innovative and trusted brand to a wider consumer audience."