Hedley was a British zoologist. He was born in 1928 to Henry Armstrong Hedley and Margaret Hopper. He was educated at Durham Johnston School, followed by King's College at Durham University (now Newcastle University) where he obtained a Bachelor's degree in Zoology and a PhD in 1953.
He was first employed at the Natural History Museum in 1955. In 1971 he was appointed Deputy Director of the museum and in 1976 became Director of the museum. In 1988 he retired from the Natural History Museum.
From 1977 to 1980, Hedley was the Honorary Secretary of the Zoological Society of London.
Hedley married Valmai Mary Griffith in 1957 and they had one son. He died aged 77 on 11th July 2006.