Nottingham worked at the Publicis Groupe shop for eight-and-a-half years. Before this, she was at Grey London for four years.
At Starcom, Nottingham helped to change the way the agency bring in talent and pulled together top learning and development programs. Such initiatives meant that the agency was in The Sunday Times Top 100 rankings for three years.
It was also awarded the Mumsnet Gold Family Friendly awards for its "creative and leading edge work around parents".
At R/GA London, Nottingham will report to Matt Lodder, the executive vice president managing director for R/GA EMEA. She takes over from Jenny Pigott, who has left after eight years, today.
Lodder said: "Diversity has always been critical to our success at R/GA, but none more so than now. As the company continues to broaden our core offerings to include consulting, venture studios and connected spaces, it has become more important than ever."