Alsop was the son of the Rector of South Collingham,[1] Nottinghamshire and was educated at St John's College, Cambridge.

[2] He received deacon's orders from a bishop, and settled as assistant-master in the free school of Oakham, Rutland.

He was thus converted to King's religious beliefs, and received ordination in the Presbyterian denomination, not being satisfied with that which he had from the bishop.

A book against William Sherlock, dean of St Paul's, called Antisozzo (against Socinus), written in the vein of Andrew Marvell's The Rehearsal Transpros'd, made him a name as a wit.

[3] As a result of the involvement of his son in alleged treasonable practices, he had to appeal to and obtained pardon from James II of England.