Eyre was born into an ancient Wiltshire family which acquired Great Chalfield manor, along with the constableship of Trowbridge castle, through marriage in 1563. His grandfather served as a knight of the shire in that same year, while his father achieved the same distinction in 1597. Eyre enjoyed kinship ties with several other prominent Wiltshire families, his mother, Anne, being a Bayntun, while his sister married the eldest son of Sir Walter Long†.
Eyre was knighted in 1605, shortly before accompanying Charles Howard†, 1st earl of Nottingham on his embassy to Spain. In 1609 he was licensed to travel abroad for three years. However, he can have made little use of this grant, for in the following year he was in London when he attempted to murder Sir Edward Herbert*, whom he suspected of conducting an affair with his wife. This assault was referred to the Privy Council, but though denounced by the duke of Lennox as ‘the most miserable man living’, Eyre escaped serious punishment, possibly because he had been aided and abetted by several attendants of another major courtier, the 1st earl of Suffolk.
Eyre was first talked of as a potential ambassador to Constantinople in November 1616, but he did not secure this appointment until July 1619, when he was recommended by the royal favourite, the marquess of Buckingham.
In February 1625 a Venetian diplomat at Florence reported that one John Acre was being sent as James I’s representative to Bethlen Gabor, prince of Transylvania. This man may have been Eyre, but if so, no further details of this mission have emerged.
Eyre succeeded his father at Great Chalfield in 1629, but sold the manor two years later to Sir Richard Gurney, lord mayor of London, and thereafter resided at St. Giles-in-the-Fields.
