The Gilded Age originated as a planned spin-off prequel to Downton Abbey, initially conceived as a book and centered on Lord Grantham and Cora's romance before evolving into an independent series.

The show was originally announced for NBC in January 2018 with an order of ten episodes for a planned 2019 premiere, but in May 2019 the project moved to HBO instead, ultimately premiering with nine episodes in January 2022.

Amanda Peet was originally cast as Bertha Russell in 2019, but she was replaced by Carrie Coon in April 2020 due to delays caused by the COVID-19 pandemic.

The costuming team changed their approach after Carrie Coon replaced Amanda Peet, using Coon's own presentation as inspiration to create more metallic-colored dresses evoking the burgeoning machine age.

Filming began in Newport, Rhode Island in February 2021 at real historic mansions including Chateau-sur-Mer, The Elms, and The Breakers, with a casting call for local Rhode Islanders as extras issued in December 2020.

For season two, production used Manhattanville College's Reid Hall, a mansion designed by architect Stanford White in 1892 for newspaper publisher Whitelaw Reid, to portray multiple different locations including offices, a home parlor, and an art gallery.

During production, a horse collapsed and died on set, prompting PETA to call for an investigation; HBO later stated a veterinarian's preliminary findings suggested the death was likely due to natural causes.

The characters Bertha and George Russell are believed to be at least partly inspired by real-life socialite Alva Vanderbilt and her husband William K. Vanderbilt, who famously used a lavish housewarming ball to force their way into New York's elite high society ruled by Caroline Astor.