Isabelle is the younger sister of Vianne, driven by a hunger for affection due to a difficult childhood. She becomes a key member of the French resistance under the codename "Nightingale," devising escape routes through the Pyrenees for downed Allied airmen.

Julien is the estranged father of Vianne and Isabelle, traumatized by his WWI service. He struggles with guilt over his inability to be a father to his daughters.

Gaëtan is a young communist and resistance fighter who forms a romantic relationship with Isabelle during the war.

Beck is a German officer billeted at Vianne’s home. He develops a complex, eventually tragic relationship with Vianne.

Rachel is Vianne’s neighbor and best friend who faces persecution due to her Jewish heritage during the German occupation.

Von Richter is an SS officer overseeing the deportation of Jews in Carriveau and becomes an antagonist to Vianne.

Sophie is Vianne and Antoine's daughter, forced to grow up quickly during the war due to its hardships.

Antoine is Vianne’s husband and a postman conscripted and captured during the war, affecting the family deeply.

Paul Lévy is a friend of Julien Rossignol and a member of the resistance network, eventually arrested.

Anouk is a resistance member who helps Isabelle gain acceptance into the network in Paris.

Ari is Rachel's son left in Vianne's care during the war, for whom Vianne poses as the mother to protect him.

Henri is a leader in the local resistance, aiding Vianne in forging papers for Jewish children.

Micheline is an old family friend who aids Isabelle in smuggling airmen out of France, becoming a mentor to her.

Julien is Vianne's son, raised in America and becoming a surgeon, who later seeks to understand his mother's past.

Marie-Therese is the mother superior at the convent who helps Vianne hide Jewish children during the war.