Simon Astley is moving to the new post of head of public affairs later this month, after seven years at BAE.
Before joining the defence, security and aerospace firm, he headed external and public affairs at the Civil Engineering Contractors Association.
Balfour's lobbying efforts are currently overseen by company secretary Chris Vaughan and director of corporate comms Duncan Murray.
The firm recently switched its public affairs business to Edelman after more than four years with Weber Shandwick.
