Of Winkfield Green, Wiltshire; educated at Sidney Sussex College, Cambridge, he was rector of Hargrave, Northampton, and curate of Westwood (1841-54). He was the nephew of Thomas Martyn, the Cambridge biologist.

CORRESPONDENCE OF John Martyn Longmire:

Robert Southey to John Martyn Longmire, 4 November 1812 in The Life and Correspondence of Robert Southey (London: 1849-1850)