The origins of this name are not entirely clear. There was a family with that name that occupied or owned properties from Claxfield to Cellar Hill (but which came first? the place or the family name?) and further afield. Alternatively, as so often happened, old roads and tracks went through periods of neglect and decay, and "greened up". This old Roman (and pre-Roman) road (Watling Street) has ebbed and flowed in its importance and traffic.
Other names for what is now "London Road" include Key or Clay Street (with echoes today in Keycol Street to the West). For much of recorded history, Greenstreet was the largest and most important community in this area. But as Teynham grew with industrial-scale brick-making to help build London, and the stimulation of the railway, the importance of Greenstreet ebbed as a thoroughfare. The increasing mechanisation of farming also led to a decline in supporting trades that had underpinned the earlier growth and importance of Greenstreet.