McErlane - who worked on clients including Tourism Ireland and the Police Service of Northern Ireland - reports to Will Chambré, managing partner of the Belfast-based outfit.
Before his two-and-a-half years at WS Belfast, he spent four years at NI public affairs consultancy Stratagem, and worked as a researcher in Dublin at the Institute for European Affairs.
Chambré has four full-time and four part-time associates. Clients include the General Medical Council and the Federation of Small Businesses.