Newton is responsible for strategically managing Grass Roots' supply chain for events and communications, and is based in the agency's London office.
Newton said he would ensure Grass Roots took a consistent approach to managing supplier relationships, introduce a supplier-performance measurement system and communicate supplier lists through the agency.
"I will start with the UK and Europe and then extend the approach worldwide," he said.
Newton will also consult with clients on the consolidation of their events programmes to help them reduce expenditure.
Grass Roots global head of events Nick Bender said: "We're working with an increasing number of clients globally, handling hundreds of events annually and this approach will ensure we continue to offer them the best value and a more streamlined approach to purchasing throughout the business."