In 1956 he travelled to Australia for the Olympic Games, and stayed on, working at Myer and Kia-ora, and for a year he was a senior designer at Ogilvy & Mather. In 1968 he started his own agency called Neish, Tutt Grunwald Advertising.

The agency was responsible for a wide range of projects including corporate image and packaging programmes for clients such as Hoechst Company, Lance of Paris, Perfumes Guy Laroche, Tessa Furniture and Adidas.

As well as creating direct mail, packaging and corporate identity campaigns for his clients, Grunwald was commissioned by the Department of Trade and Resources to prepare major exhibitions in Lima, Bangkok, Milan and Tokyo.