John was a younger son of the prominent Wiltshire lawyer Robert Long, and some five years the junior of Henry Long, who was the first of the brothers to enter the Commons.
Long’s marriage may have taken place before his election to Parliament in 1442, but even so he was still a young man, perhaps under age, with no experience of local administration to commend him to the electors. His father sat in the same Parliament for Salisbury, and his brothers Henry and Richard represented other Wiltshire boroughs. That Robert and three of his sons should all be elected together indicates the extent of his political influence in the county, bolstered as it was by his position as bailiff of the liberties of Bishop Aiscough of Salisbury and his close association with Sir Walter Hungerford†, Lord Hungerford. John never became such a prominent figure in the locality as his father or older brother Henry; nor was he ever formally linked with figures of importance or appointed to office by the Crown. Furthermore, he was rarely named as a feoffee, although in the autumn of 1443 he was party to a transaction whereby property in Wootton Bassett was settled on John Gibbs and his wife.
John served as a juror at the inquisition post mortem on (Sir) John Lisle II* at Salisbury in October 1471, and at the belated inquiries about the late Sir John Popham*’s estate at Malmesbury five years later.
