After graduating in industrial design from San Jose State University in 1981, Robert co-founded the design consultancy Lunar. Subsequently, he was hired as Director of Industrial Design for Apple Computer where he served for seven years. In 1996, he was appointed partner in the international firm Pentagram, helping lead the San Francisco office. In 2006, Brunner and entrepreneur Alex Siow launched the start-up Fuego, a new concept in outdoor grilling. In 2007, Robert founded Ammunition, focusing on the overlap between product design, brand and experience. He continues to lead Ammunition and Fuego concurrently.
In 2008, Robert co-authored the book Do You Matter? How Great Design Will Make People Love Your Company with Success Built to Last author Stewart Emery. He also teaches advanced product design at Stanford University.