Fee's career took off with her leading role as Sophie Kellermann in the television series Allein gegen die Zeit.

In the summer of 2012, the shooting of a film adaptation of the children's book Die schwarzen Brüder with Moritz Bleibtreu took place, in which Ruby O.

In the summer of 2013, Fee appeared in front of the camera for Detlev Buck's film Bibi & Tina [de] as Sophia von Gelenberg.

Mach dein Ding (2020), plays Paula aus Sankt Pauli, immortalized in the song "Alles klar auf der Andrea Doria" by Udo Lindenberg.

In 2021, Ruby played the role of Korina in the film Army of Thieves, directed by Matthias Schweighöfer, who also starred in the movie.