Eyre came of a legal family, his grandfather, Robert, having been a bencher and reader of Lincoln's Inn, and his father being a barrister, Robert Eyre of Salisbury and Chilhampton, who married Anne, daughter of Samuel Aldersey of Aldersey in Cheshire.
[1] In 1660, his mother wrote to him, telling him to think deeply about his marriage plans, advising "when done, not to be undone, and done either happy or unhappy".
When Charles Knollys' claim to the earldom of Banbury came before the House of Lords in 1698, Eyre was called on, along with Chief Justice Holt, to state to the house the grounds upon which he had given judgement in favour of Knollys, who being tried in the King's Bench in 1694 for murder had pleaded his privilege as a peer.
A monument was erected at Lancaster to him, and his body was removed to St. Thomas's, Salisbury, the family burial-place, on 2 July 1699.
He and Martha had six children; the eldest son, Sir Robert Eyre, was judge of the queen's bench.