Dom Cobb
Dom Cobb (Leonardo DiCaprio) is the protagonist of Inception. He is a professional dream extractor, spy, and thief who uses military-grade technology to infiltrate people's dreams and retrieve their secrets. Cobb is trained in dream-sharing technology by Stephen Miles, a professor of architecture and Dom's father-in-law. Cobb is also a criminal, unable to return to the United States under suspicion of killing his wife Mal, who still haunts his subconscious. Cobb agrees to Saito's inception plan as a way to return to his home country and reunite with his children.
Ariadne
Ariadne (Elliot Page) is a promising graduate student in architecture whom Stephen Miles recommends to Dom Cobb as a builder of dreamscapes—complex, maze-like environments that help ward off projections. She helps Dom and his team try to execute their most ambitious operation yet: to perform inception in a three-tiered dream. Although Ariadne is initially disturbed by the content of Cobb's dreams, she is lured back into the scheme by the limitless and awe-inspiring architectural possibilities of dreams. Ariadne also pushes Cobb to confront Mal and disclose his inner torment to the rest of the team.
Arthur
Arthur is Cobb's resourceful partner and second-in-command: a "producer" of sorts who plans, organizes, and researches all his missions. Arthur plays many roles, at times giving Cobb advice, providing background information, scouting locations, counseling Ariadne, and administering "kicks." Arthur opposes Saito's inception plan and advises Cobb to turn it down, but Cobb ignores him. Cobb later scolds Arthur when his research fails to turn up the fact that Robert Fischer has militarized his subconscious.
Eames
Eames (Tom Hardy) is a British forger whom Dom recruits in Mombasa to join the team in their efforts to pull off Saito's inception plan. Eames gives Cobb and the rest of the team crucial advice about how to perform inception, telling them that the idea must be exceedingly simple, and seem self-generated. As a skilled forger, Eames is easily able to take the guise of other people in dreams. Eames is also described as a "fence"—someone who buys stolen goods and resells them for profit.
Saito
Saito is a wealthy Japanese businessman who is the target of Cobb and Arthur's first dream infiltration. Saito explains to Cobb that the operation is in fact an "audition" for a plan of Saito's own, which involves "incepting" an idea in the mind of his business rival, Robert Fischer. Saito and Cobb form an uneasy alliance so that Cobb can reunite with his children in the United States, in exchange for helping Saito secure his empire. At the end of the film, Cobb must rescue Saito from "limbo," a scene also glimpsed in the opening sequence.
Yusuf
Yusuf is a Kenyan chemist whom Cobb recruits in Mombasa. Yusuf is able to produce a sedative that induces the kind of deep sleep necessary for inception. Yusuf shows Cobb a small group of permanent dream-sharers in his basement, who prefer the world of dreams over the world of reality. Although Yusuf's sedative induces a sound sleep, the sleeping person remains sensitive to the "kick" that brings one out of a dream. In Saito's plan, Yusuf is tasked with driving a van in the "first" layer of Robert Fischer's dream.
Robert Fischer
Robert Fischer (Cillian Murphy) is the billionaire scion of his father's powerful energy company, also Saito's primary business rival. The failing health of Robert's father Maurice ignites a power struggle between Robert and his uncle Peter over who will control the company. Although Robert is desperate for his father's approval and committed to leading the company forward, Saito wants Cobb and his team to "incept" the idea in Robert to instead break up his father's empire. They achieve this by convincing Robert that his father wanted him to live his own life rather than follow in his footsteps.
Mal Cobb
Mal (Marion Cotillard) is Cobb's dead wife who still haunts his subconscious. Cobb and Mal had two children together, and acquired an interest in dream-sharing under the tutelage of Mal's father Stephen Miles. Mal spends fifty years in limbo with Cobb, and grows to prefer the world of dreams to the world of reality. In order to return to reality and be with their children, Cobb "incepts" the idea in Mal that their world is fake and they must wake up. Upon awakening, Mal continues to believe she is dreaming, and commits suicide. Cobb's lingering guilt over her death causes her projection to violently invade his dreams.
Stephen Miles
Stephen Miles (Michael Caine) is a college professor who lives in Paris, and is Cobb's father-in-law. Miles is also Cobb's mentor, the first person to introduce Cobb and Mal to dream-sharing technology. Miles acts as a go-between for Cobb and his children, given that Cobb cannot return to the United States to be with them under suspicion of killing Mal. Miles is begrudging about Cobb's use of dream-sharing technology for criminal acts of theft and espionage, but nevertheless recommends a skilled graduate student in architecture to join Cobb's team. Miles later greets Cobb at the airport after he successfully performs inception and is able to return to the United States.
Nash
Nash (Lukas Haas) is the dream architect in Cobb's first operation involving Saito. Nash creates a dream-within-a-dream so that Cobb and Arthur can retrieve business secrets for the Cobol Corporation. After the mission fails, Cobb and Arthur upbraid Nash for an inconsistency in the carpeting in Saito's apartment, which causes Saito to realize he is dreaming. Nash is later revealed to be a traitor, but rather than kill him, Cobb turns him over to Cobol. Nash's actions force the team to find a new architect.
