The church, restored in 1870, has a single-cell nave but there are two blocked arches of an arcade on its N side. There are two doorways, a round-headed N doorway, now blocked, and a pointed S doorway sheltered by a porch. The transept carries a central tower, and there is a square-ended chancel. Romanesque sculpture is found in the S nave doorway and on a capital supporting the modern font.

East Dean is not mentioned in the Domesday Survey. It formed part of the prebend of the collegiate church of Arundel, which was given to Chichester Cathedral in 1150.

Peat and Halsted reported that the upper part of the original font was 'broken up and built into the walls'.

Nairn and Pevsner dated the S doorway toc.1200, noting that the capitals were, ' . . . on the way to becoming crockets'. Although on every capital the tip of the axial leaf is broken, none appear to have been tightly curled, and so the reference to crockets is unjustified. The doorway is more likely to date from the last quarter of the 12thc.

Of the font base, Nairn and Pevsner wrote: 'But the base looks just like a large upturned capital with multiple trumpet scallops. And that, surely, is what it was - not reused from the church, but brought in by the 12thc. as their equivalent of Government surplus.'