Miller became a member of the Society of Chemical Industry's horticulture group and also its membership advisory committee after serving as IoH president from 2004 to 2006.
His career began as a gardener in Swindon parks in 1951. Miller later worked as a gardener at Column Minor in Newquay and as a gardener in Bristol parks.
From 1962 to 1969 Miller worked in the botany department at the Advanced College of Technology in Bristol. From 1969 to 1992 he worked at Guernsey Advisory Service, latterly as its director.
He served as president of the Guernsey Growers' Association and was also a founder member of the IoH.
Miller helped Raymond Evison establish Guernsey Clematis Nursery and was its general manager from 1992 to 2004. He was also a member of the group that stimulated the formation of the Eden Project in Cornwall in 1997 and he continued to work for the project in later years as a consultant.
Miller was awarded the MBE for services to horticulture in Guernsey in 2009.