The New York office marks Purity's first expansion outside of the UK. The move is in response to a growth in international campaigns that the agency is working on for clients.
Purity New York will be headed up by business director Baqer Keshwani, who will work closely with the agency’s offices in London and Bedfordshire.
Purity Managing Director Rob Quinn said: "Having a US presence will provide an opportunity to grow new business and also extend our offering to existing clients who are increasingly looking to run international campaigns.
"Over the past 12 months we have supported on a number of cross-border projects for the likes of Samsung, Microsoft, Vodafone and Lego, with further global initiatives in the pipeline."
The agency is currently in talks regarding a US inter-state tour and a major on-trade activation based in New York.