Barnett will work with the founders to promote key themes such as urbanism, productivity, entrepreneurship and creativity.
The primary aim of the role is to establish the start-up as a world-leading brand.
Second Home was co-founded by Rohan Silva, former adviser to David Cameron on innovation, and Sam Aldenton, creator of east London event space Dalston Roof Park. It provides office space for entrepreneurs and creative businesses.
Before stepping into the world of PR, Barnett worked at Sky News in a variety of roles from multimedia producer through to online politics producer.
In 2012, Barnett joined SwiftKey as vice-president of global comms to oversee the comms strategy, media coverage and reputation of the brand.
The SwiftKey in-house team won PRWeek's Best Places to Work award in 2014 and was runner up in 2015.