A painter, photographer, musician and writer, Dannatt began his professional career working for the family business as a surveyor.
After service in the army in 1944, Dannatt took up the position as a music critic for the News Chronicle. By 1948 he had taken an avid interest in photographing the Dorset coast. The complex methods of photography in the '40's taught him a lifetime technique of observation and meticulous attention to detail. Soon this interest developed into painting and by 1956 he was fully immersed into the Cornish art scene. He became an associate of the Penwith Society of Art and Newlyn Society of Arts. With his reputation growing for hard-edged abstracts, Dannatt struck up friendships with established artists in St Ives. In 1975 the Orion Gallery in Penzance held a mixed exhibition of works by Dannatt, John Wells and Alexander Mackenzie.
Dannatt's first retrospective exhibition of work (1960-1981) was in 1981 at the Newlyn Art Gallery. Dannatt later exhibited regularly throughout Cornwall and Europe, including Galerie Schreiner in Switzerland and more recently with Osborne Samuel in 2005.
In 1986 George and Ann Dannatt established 'The George Dannatt Trust,' which was to promote the education of visual arts.
The monograph George Dannatt One Way of Seeing was published in both English and German in 1990 to highlight the artists oeuvre.