Seaford church has a W tower, an aisled nave with two-bay arcades and a S porch, a non-projecting transept, a large chancel with a polygonal end and a N chapel. The Perp tower seems to have been erected within the W bay of a Norman nave, but the W doorway is neo-Norman rather than Norman. Herringbone masonry suggests that the N aisle is of Norman origin, but the present two-bay nave arcades, clerestoreys and corbel tables appear to date from the early 13thc. One capital in the S arcade is historiated, with the Baptism of Christ, the Harrowing of Hell, Daniel in the Lion's Den, the Massacre of the Innocents, and the Crucifixion. The mid-Victorian 'transepts' and chancel were designed by John Billing and erected in 1861-62.

Seaford was one of the Cinque Ports and could afford a large church. The large St Michael fragment is thought to have been dug up in the churchyard in 1778, when 'the site of the old burnt chancel was explored' (SNQ 1940-41). The small fragment was found during restorations in the 1930s (?) by WH Godfrey.

Stylistically, the St Michael fragments are closely related to the Chichester Reliefs (c.1125-35). It has been suggested that they came from a tympanum. Taylor suggested that this tympanum was located at the west end of the church where, in 1813, Frederick Shoberl noted 'a spacious entrance under a pointed arch, above which are the remains of another circular form, the intermediate space being walled up'. Apparently, the 15thc.doorway, with traces of its predecessor, survived until 1894-95, when a new W doorway was put in. During the work, the architect found a base, capital and part of the jamb shaft of the earlier doorway (in 1940-41 this was in the Barbican Museum, Lewes).

The form of the font (a square bowl on five columns) suggests that it might be of 12thc. or 13thc. origin, although its various elements have been replaced or renewed over time (for photograph see: Drummond-Roberts 1935, 74). It was not recorded.