Emma Watson took over the role of Meg March from Emma Stone, who became unavailable due to scheduling conflicts with promoting The Favourite (2018). Ironically, Stone previously took over the role of Mia in La La Land (2016) after Watson dropped out of the project due to the commitment of her role as Belle in the Disney live-action remake of Beauty and the Beast (2017).
Greta Gerwig was originally tasked by Sony Pictures to write a new screen adaptation of Louise May Alcott's novel after the studio had rejected earlier scripts by Olivia Milch and Sarah Polley. However, after the success of Gerwig's Lady Bird (2017), Sony Pictures hastily offered Gerwig the chance to direct this film using her script in the hopes of forcing the delayed project into production after years of development hell.
With her role as Jo March, this is the second time that Saoirse Ronan will portray one of Katharine Hepburn's iconic roles after Mary, Queen of Scots (in which she portrayed the titular character in Mary Queen of Scots (2018)). She also shared a common bond with Winona Ryder, who played Jo in the 1994 version of Little Women (1994). Ronan played Abigail Williams in the 2016 Broadway revival of "The Crucible", the same role that Ryder played in the 1996 film.