It is the ancient parish church of Hangleton, an isolated South Downs village that was abandoned by the Middle Ages and was open farmland until the Interwar Period, when extensive residential development took place.

[1] Hangleton existed at the time of the Domesday Book of 1086, although the church was not mentioned; its first known reference is in 1093 when William de Warenne, 2nd Earl of Surrey put it under the control of Lewes Priory.

The condition of the church building worsened, but it never became an unusable ruin and never experienced a period without services—although for a time these were as infrequent as once a year.

[10] Following the 1949 alterations, St Helen's was reopened for regular use,[9] and was granted Grade II* listed status on 24 March 1950.

It may also have served as a type of confessional, allowing a priest to sit inside the church and the penitent to stay outside.

[6] In one corner of the chancel, there is a memorial monument which has been identified[6] as representing the Bellingham family, who lived in the area in the 16th and 17th century.

[5][6] Elsewhere, an early-20th-century stone pietà commemorates a local brewer and pottery collector, and a carved wooden screen and reredos in the chancel was also donated as a memorial.

[12] Edward Vaughan Hyde Kenealy QC, who lived in Portslade from the 1850s until 1874,[13] was a barrister who unsuccessfully defended Sir Roger Tichborne in the Tichborne Case, a famous 19th-century trial: it was the longest in British legal history at the time, partly because of Kenealy's erratic, inappropriate behaviour.

[11][12][14] He is buried in a grave by the south door of the church, marked by an ostentatious black marble tombstone with gold mosaic work.

[11] Henry Willett (1823–1905), a wealthy Brighton brewer, and noted collector of ceramics, paintings and fossils was buried here.