His father, William (one of a family of thirty-nine children by the same father and mother), was a counsellor-at-law, who lived first in London and then retired to a family estate at Abbot"s Langley, Hertfordshire, where Joseph was born and baptised in February 1703-1704.
He was educated at Sidney Sussex College, Cambridge, graduated Bachelor of Arts in 1726, and was admitted Master of Arts
Greenhill was a nephew of Thomas Greenhill. in 1731. Greenhill was appointed rector of East Horsley in 1727, and of East Clandon in 1732, both livings in the county of Surrey, and small both as to population and emolument. He lived at East Horsley, and died there in March 1788.
