[1] He was named after a close friend of his father, Erasmus Lewis, secretary to Lord Oxford.
After serving an apprenticeship in Liverpool under major Liverpool slave trader Foster Cunliffe,[2][3] he became a partner in a Newcastle coal dealership and was for some years Chief Steward of the lead and coal mines of his 2nd cousin Sir Walter Blackett.
He was one of the original partners of the Newcastle upon Tyne Fire Office, now part of Aviva plc.
John Erasmus Blackett died in Newcastle on 11 June 1814 and is buried in St. Nicholas's Church.
[5] Some references [6][4] state that Blackett Street in the centre of Newcastle was named after him but recent research has cast doubt on that.