After finding out that the adaptation was in the works,
Saoirse Ronan reached out to
Greta Gerwig and told her she decided she was going to play Jo March. Gerwig was initially hesitant to cast Ronan after having just worked with her on
Lady Bird (2017), but after realizing that more or less casting herself was a very Jo thing to do, Gerwig sent Ronan an e-mail that said "Yes, you're Jo."