Gregg was born and brought up in Cornwall and still lives and works in the county. He studied at art college and later became interested in glass.
His early glass work was greatly influenced by the colours and effects he found in the deposits of metal ores in the old mine workings he explored as a child. He originally used mineral foils in his coloured glass work.
More recently he has worked with coloured glass powder to create flowing and organic line and develop new textures. He has developed techniques for working with glass powders that are unique to his work, which creates an ususual textured look in the glass, a process which requires a long time in the kiln and which allows the work to take on its organic form.