Tom Jenkins has been hired as account director to work on the agency's Mercedes-Benz account. He was formerly senior account manager at The Frank Agency.
Jenkins' remit includes overseeing incentive programmes and events, dealer communication and management information systems.
"With the volume of work increasing in 2012, Tom has joined us to manage the account team and ensure that we continue to deliver a high-quality service," said managing director Phil Dunk.
Georgina Fayers, former Grass Roots operations manager for digital marketing and loyalty, has also been appointed as account manager. She will have day-to-day responsibility for one of River's largest clients.
The performance improvement specialist recently won two Gold Awards at the 2012 Institute of Promotional Marketing Awards for its work with Jaguar, Land Rover and Glow-worm.