Irina is a young Russian-speaking American who applies for a CIA typing pool job despite lacking strong typing skills. Because her father was arrested in Moscow before her birth, she harbors a quiet resentment toward the Soviet state. She naturally prefers to fade into the background, a behavioral pattern her superiors quickly identify as valuable for intelligence work.

Olga is the mistress and unofficial literary agent of the famous Russian writer Boris Pasternak. She operates as his muse and fiercely protects him from state scrutiny. Cultured and determined, she faces brutal interrogation by the KGB regarding Pasternak's political leanings and his unfinished manuscript.

Sally is a glamorous former OSS agent who returns to work for the CIA. During World War II, she served successfully as a "swallow"—an agent using physical attractiveness and charm to extract intelligence. Frustrated by the mundane desk jobs offered to women post-war, she seeks active fieldwork and takes Irina under her wing.

Boris is a celebrated Russian poet and author currently writing the controversial novel Doctor Zhivago. Nicknamed the "Cloud Dweller" by Stalin, he enjoys a small measure of state protection but remains deeply conflicted about his art and personal life. He often prefers the quiet of his writing desk over confronting the physical dangers his subversive work poses to his loved ones.

Teddy is a CIA operative working in the Soviet Russia Division. A lover of Russian literature, he firmly believes books can be weaponized to spread democracy. He takes an early professional interest in Irina, teaching her the fundamentals of espionage through exercises that quickly lead to a complex personal relationship.

Henry is a fast-rising CIA agent with a reputation for aggressive and entitled behavior. The women in the typing pool actively dislike him due to his past harassment of female staff. His exceptionally quick promotion through the ranks raises suspicions among clandestine operation leaders.

Semionov is a KGB agent tasked with extracting a confession from Olga Ivinskaya. He uses psychological pressure and physical exhaustion to seek evidence of anti-Soviet sentiment in Boris Pasternak's writing.

Zinaida is Boris Pasternak's legal wife. She presides over his country dacha, known as Big House, maintaining a sense of domestic normalcy while silently enduring her husband's highly public affair.

Ira is Olga Ivinskaya's daughter. Living in Moscow, she relies heavily on her mother and experiences intense anxiety regarding the constant government surveillance surrounding their family.

Mitya is Olga Ivinskaya's young son. He enjoys spending time in the country near Peredelkino but struggles to understand the complex political dangers surrounding his mother's romantic life.

Anderson is a CIA boss in charge of the typing pool. A former OSS operative who served with Sally Forrester in Ceylon, he frequently overlooks the broader capabilities of the women under his command while hiring based on what he perceives as hidden talents.

Frank is the leader of the CIA's clandestine operations. He recognizes the strategic utility of deploying female operatives and assigns sensitive internal investigations to trusted former colleagues.

Sergio works in Moscow translating bulletins into Italian. Acting as a literary scout, he actively seeks a new masterpiece for an Italian publishing house and approaches Boris Pasternak about obtaining his manuscript.

Feltrinelli is an Italian publisher and member of the Italian Communist Party. He possesses a strong desire to publish Doctor Zhivago globally, largely disregarding the severe physical danger this action poses to the author.

Polikarpov is the head of the Central Committee's Culture Department. He applies intense governmental pressure on Pasternak and Olga to conform to the state's strict cultural guidelines.

Irina's mother is a Russian immigrant who works tirelessly as a seamstress in Washington, D.C. Having lost her husband to the Soviet regime, she focuses entirely on her dressmaking business and securing a safe, traditional domestic life for her daughter.

Buinaya is a Ukrainian woman imprisoned in the Gulag for stealing flour to feed her family. Holding a longer sentence than Olga, she resents Olga's educated, bourgeois background and targets her physically.

Norma is a member of the CIA typing pool who originally wanted to be a published poet. She shares the collective frustration of the female staff regarding their male colleagues' dismissive and highly inappropriate behavior.

Gail is an engineering degree holder relegated to the CIA typing pool. She is frequently frustrated by being singled out for being Black and uses her technical skills to independently verify intelligence, such as tracking satellite broadcasts.

Linda works in the typing pool alongside Irina. Like the other women, she is highly capable but underutilized by the Agency, frequently swapping stories of workplace mistreatment with her peers.