The series was created by Heidi Thomas, originally based on the memoirs of Jennifer Worth, who had worked with the Community of St. John the Divine, an Anglican nursing order founded in 1849, in London's East End.

Heidi Thomas received a specific blessing from Jennifer Worth to continue the series and had a fruitful collaboration on future plans before the author's death; after Jessica Raine's departure at the end of series three, Worth's family stated the show no longer resembled her stories, though her husband acknowledged it retained the 'spirit' of her works.

The ship seen in the opening titles is the Shaw, Savill & Albion Line liner QSMV Dominion Monarch, filmed in dry dock at King George V Dock, with the accompanying road shots filmed on Saville Road, Silvertown, east London.

Many exterior scenes are shot at The Historic Dockyard Chatham, which stands in for East London streets and buildings.

Nonnatus House was originally filmed at St. Joseph's Missionary College in Mill Hill, North London, but after the building was converted into luxury flats, a new Nonnatus House set was built at Longcross Studios in Surrey.

HMS Cavalier is used for shipboard scenes, the order's mother house is filmed in West Wittering, and a reconstructed prefab house at the Chiltern Open Air Museum in Buckinghamshire has also served as a filming location.

For the first three series the score and title theme were composed by Peter Salem; since series four, the music has been composed by Maurizio Malagnini, who described the orchestral score as 'a diary of the emotions of the series.'

In October 2023, a group of academics suggested the show should carry a health warning over its depiction of 'inaccurate' birthing practices, to which the production responded that it was a period drama, not a documentary, and 'highly accurate to the time it depicts.'