Unwin joins alongside two new project managers, ex-event producer at Brainstorm Communications UK Kirsty Beck and Laura King, who was previously an event consultant at Carlson Wagonlit Travel.
Unwin has more than twenty years of experience in the events sector, including roles at Fiat and Daewoo, before it merged with General Motors.
At Kia Motors Unwin held the position of head of events and sponsorship, launching five new models into the market, before becoming marketing & events director at SsangYong.
Most recently Unwin was marketing manager UK & ROI for agricultural equipment manufacturer Case New Holland.
Grass Roots Eventcom director Warren Hillier said: "Nigel’s experience in brand management, product launches, promotions, events and travel incentives is a perfect fit with the requirements of our automotive clients. We are very excited that he, Kirsty and Laura have joined to help us build on our good first half to the year."