Garland, who was previously director of stakeholder engagement at Green Issues Communique, has been tasked with driving the growth of the practice.
Westbourne founder James Bethell said: "Stakeholder engagement is a growing part of Westbourne Communications’ business. It’s also a discipline that clients are taking more and more seriously.
"Westbourne is broken into two practices: Change Opinion and Engage Opinion. Decisions are increasingly made in a bottom-up way and forward-looking businesses recognise this.
"James has a proven understanding of how to engage with stakeholders across the field and we look forward to him expanding this part of our business."
Garland, who started his new role last week, added: "Westbourne Communications is making waves at the moment. The opportunity to join such a thriving and hungry agency at a time of rapid growth is one I could not refuse."
The practice also includes account director Lucy James and account manager James Wickett-White.