Keira Knightley was originally cast as Cora Seaborne and was also set to serve as executive producer when the series was announced in August 2020, but she left the project in October 2020 for family reasons.

Claire Danes signed on in February 2021 to replace Keira Knightley in the lead role of Cora.

Tom Hiddleston joined the cast in March 2021, the month after Claire Danes was confirmed.

Frank Dillane, Hayley Squires, Clémence Poésy and Jamael Westman were all added to the main cast in April 2021.

Filming was originally expected to start in late November 2020, but was delayed after Keira Knightley's exit from the project.

Principal photography took place from February 2021 to the week of 27 June 2021, with locations including Alresford, Brightlingsea, North Fambridge and Maldon in Essex, as well as Gordon Square in Bloomsbury, London.

Costume designer Jane Petrie won the BAFTA TV Craft award for Best Costume Design for her work on The Essex Serpent.

The miniseries received two nominations at the Royal Television Society Craft & Design Awards, for Design — Titles and for Production Management.