The original part of the settlement was laid out in the early 19th century as a new town: a place of elegant houses designed for the well-off; it also included a central public garden, a hotel, an archery, assembly rooms and a church.

The land that is now St Leonards was once owned by the Levett family, an ancient Sussex gentry family of Norman origin who owned the adjacent manor of Hollington, and subsequently by their descendants, the Eversfields, who rose to prominence from their iron foundries and widespread property holdings during Tudor times.

It included a house for himself (West Villa: now 57 Marina); service areas were provided, such as shops and laundering (Mercatoria and Lavatoria),[6] as well as public buildings for entertainment and the picturesque siting of villas amongst the wooded slopes and water of the central gardens, to be paid for by subscription.

[citation needed] Before he died in 1837 St Leonards (Royal Victoria) Hotel, the South Colonnade, an archway marking the town boundary with Hastings,[8] and tall seafront houses (as far as 71 Marina) had also been completed.

He leased a triangle of land bounded by Mercatoria, St John's Church, Maze Hill and Kenilworth Road.

He gave some land in Mercatoria for a National School, and completed his father's seafront terrace by building 72 to 82 Marina.

In 1875, the two towns merged into the County Borough of Hastings, and by then the total seafront had reached some three miles (4.8 km).

Positioned almost opposite the Royal Victoria Hotel, the shore end had a pavilion constructed of intricate ironwork at the entrance so that visitors could drive straight to the door and avoid the seafront weather.

The latter part of the town – Bulverhythe – is thought to be the original site of the port of Hastings, since cut off by longshore drift of pebbles.

In November 2023, the steep land between Marina on the sea front and the West Hill Road was affected by a series of landslips, leading to local homes being evacuated.

The Council purchased a strip of land at the southernmost tip to erect a statue of Queen Victoria which was unveiled on 31 December 1902.

The garden was purchased by the Council in 1880 and opened to the public; it consists of trees, shrubs and grass areas with a central pond.

Elizabeth Eiloart (1827–1898), novelist, retired to St Leonards, and King Solomon's Mines author Henry Rider Haggard came to live at North Lodge, Maze Hill, the house built across the road at the entrance to old St Leonards; this remained his home until 1923.

George Bristow was the taxidermist at the centre of the Hastings Rarities ornithological fraud; his business address was 15 Silchester Road.

Sheila Kaye-Smith was a prolific author whose novels are set in the Sussex countryside around Hastings and Rye; she was born in St Leonards, the daughter of a local physician and lived in Dane Road until her marriage in 1924.

George Monger was awarded a VC during the Siege of Lucknow in 1857, and after leaving the army, he lived in Tower Road, St Leonards where he died in 1887.

Archibald Belaney (b 1888 d 1938) "Grey Owl" achieved fame as a conservationist during his life, after his death the revelation of his non-Native origins and other autobiographical fabrications negatively affected his reputation.

Born in England and migrating to Canada in the first decade of the 20th century, Belaney rose to prominence as a notable author, lecturer, and one of the "most effective apostles of the wilderness" The Venerable Luke Irvine-Capel, Archdeacon of Chichester was the Priest-in-Charge of Christ Church with St Mary Magdalene and St. Peter and St. Paul from 2013 to 2014, and thereafter served as Rector (merely a legal transition) from 2014 to 2019, before his appointment as Archdeacon.

A. E. Holt White (1851-1933), author and illustrator of The butterflies and moths of Teneriffe, resided at 3 Warrior Square Terrace, St Leonards-on-Sea.

[citation needed] Baston Lodge, Upper Maze Hill, was the childhood home of Alan Turing.