The church is essentially 13thc. and comprises nave, with a N transept and S transept tower, S aisle and S and W porches, and chancel (with 14thc. additions) with a N vestry. The S aisle, vestry and W porch are 16thc. The entire church was restored by William White (1873-89). The font is the only surviving 12thc feature.

Shirwell appears three times in the Domesday Book. The first record has Brictmer (of Rillaton) as Lord in 1066 with Robert (of Beaumont) as Lord in 1086 and Baldwin the sheriff as tenant-in-chief. The second record has Wulfward as Lord in 1066 with William of Poilley and two men-at-arms as Lords in 1086 and William of Poilley as tenant-in-chief. The third record has Vitalis as Lord before the Conquest and Gilbert as Lord and Odo son of Gamalin as tenant-in-chief in 1086.