St John's has a clerestoreyed nave with three-bay aisles, the N arcade with a short 12thc. W bay separated from the eastern part of the arcade by a short length of wall. The two E bays are also round-headed, with stiff-leaf capitals of c.1200. The S nave arcade is round-headed too, but the capitals and the aisle date from the restoration of 1842. The chancel has N and S chapels; the N, of two bays has an arcade of c.1300, and is now used for a crèche and vestry. The S of one bay, housing the organ, is 19thc. Both nave doorways are under porches, but the N porch has been extended eastwards and converted for use as a kitchen and lavatories. The W tower is 13thc. in its lower parts, with 14thc. bell-openings and added diagonal buttresses, and a quatrefoil frieze and embattled parapet added at the top. The only feature described below is the N nave arcade.

In 1086 Robert held Cranford St John from the Bishop of Coutances. No church or priest was recorded. By the end of the 12thc. the church had been given to St James's abbey, Northampton. The advowson was transferred to the Bishop of Lincoln before 1272.

Dedication to St John recorded in 1300.

Benefice of Cranford (St John the Baptist) with Grafton Underwood and Twywell.

Dalton dates both St Andrew's and St John's to 'the time of King Henry II, when St Hugh of Avalon was Bishop of Lincoln.' If true this would date both churches between 1181 and 1189, but the present author knows of no reason to believe it, especially in view of the fact that the N arcades that are the earliest parts of both buildings look completely different from one another. Pevsner suggests that the W arch of the N arcade may be a reused arch from an earlier tower.