Cooper
Cooper is the protagonist of the film. His primary motivation is to exist (from a deep and meaningful place) and to explore. He's a widower and former NASA pilot who has been grounded and now lives as a farmer, raising crops in a world where the food supply is running out. While he loves his children, and believes in what he is doing on the farm, we can see that he yearns for more from life. We also begin to understand, in him, the emotional journey of someone who's had their dreams and love in the palm of their hands, only to have them taken away prematurely. When the time comes to choose to stay on the farm or accept the mission to space, he goes, and in doing so carries us, the audience, through a journey to discover what it means to love and be loved, and how to do what is right and necessary to save yourself and others.
Murph
Murph is Cooper's daughter. She is incredibly bright and enjoys learning (as evidenced by the massive bookshelf in her room). Her curiosity and passion for science are cultivated by her father's encouragement throughout her youth. When Cooper chooses to accept his role in NASA's mission through the wormhole, Murph is devastated, believing that she may never see her father again. She considers his departure a monstrous betrayal and finds herself unable to contact him until well into adulthood.
As she grows older, Murph finds motivation through her anger toward her father and the desolate state of the planet. Once she gets beyond that anger, it's her love for Cooper that helps her understand why he chose to go, and in turn allows him to help her solve the gravitational equation that will save Earth.
Professor John Brand
A former teacher of Cooper's and a leader at NASA, Professor Brand has spent decades attempting to solve the equation of gravity. Though his intentions seem clear when he describes Plans A and B to Cooper, he refuses to reveal that he actually stopped working on the equation long ago when he realized he would be unable to solve it without seeing inside a black hole. He believes that the people of Earth, including Cooper and his various NASA workers, will only be motivated to save humanity if they think their individual survival is possible, and so he falsely convinces everyone that Plan A is a viable option. His story is one of great inner conflict, as he wrestles with the impossibility of Plan A while also trying to put the species' interests before any one individual's.
Dr. Amelia Brand
Dr. Brand is Professor Brand's daughter. She is brilliant and brave, but more emotionally vulnerable than her colleagues. Brand had a love affair with Dr. Wolf Edmunds before his departure on the Lazarus missions, and struggles to remove this factor from her decision-making aboard the Endurance. She becomes the first colonizer of humanity's new planet when she reaches Edmunds' planet alone and establishes a settlement.
Romilly
A NASA astronaut on mission with Cooper, Romilly is intelligent, sensitive, and vulnerable. Despite his undeniable bravery, he struggles with the spinning of the Endurance and the daunting awareness that only a thin metal wall separates him from the infinite vacuum of space. During discussions of how to proceed with the mission, he acts as a calm voice of reason.
Romilly is arguably the film's most tragic character, as he endures 23 lonely years aboard the Endurance while Cooper and the others spend mere hours escaping Miller's planet. They return to find him time-worn and fragile, a smarter, wiser, but more delicate shell of himself. He is then senselessly killed by Dr. Mann's booby trap, turning his decades of solitude into an utter waste.
Doyle
Doyle is a NASA astronaut on mission with Cooper. He is mission-focused and willing to put his life on the line to collect data. Via his character, we understand that making a choice can mean saving the lives of others and sacrificing one's own. He dies saving Brand's life, and his death is a catalyst for her to open up to the rest of the crew about her motivations.
Dr. Mann
Like Professor Brand, Dr. Mann is a complexly tragic character driven by extreme inner turmoil. The conditions of his situation are remarkably more intense, however, as he spends decades alone on a stark, barren planet with no hope of sustaining life. Though once hailed as "the best of us" by Dr. Brand and the other researchers at NASA, Cooper and the team arrive to find Mann willing to sacrifice others' lives to save his own. He admits to his cowardice, but justifies his actions by citing his trials on the planet. His betrayal is one of the film's great ironies as he is revealed to be not a hero, but rather a personification of the human capacity for malice and deceit in the face of hopelessness. He exemplifies the spectrum of human behavior from selfless bravery to utterly selfish desperation and aggression.
Donald
Donald is Cooper's father-in-law and a grandfather figure to Tom and Murph. He is blunt with Cooper, offering advice that Cooper often doesn't want to hear, and represents a generation that was alive before Earth's present desolate state, as when he references eating hot dogs at baseball games, or watching the world go crazy with consumerist greed. He dies while Cooper is down on Miller's planet.
Tom
Tom is Cooper's oldest child and only son. He is pragmatic and does his best to endure the life that he was born into by becoming a farmer like his dad. We can surmise that Tom and Cooper are similar on the outside, but different from within: Tom wasn't born into a world where he had and then lost unlimited opportunities. Rather, it's a world where his fate was very much decided for him.
Tom endures a great deal: the loss of his grandfather who raises him after Cooper leaves, having to let go of his father when he hasn't heard from him in 23 years, working a farm that is itself dying off, losing his firstborn son to illness, and watching his family risk meeting the same end from the inhalation of dust on the farm each day. He is a character who fights to right by his family and maintain hope for the future, even if his efforts are likely futile.
Dr. Getty
Dr. Getty is the adult Murph's colleague and friend, a confidant she can talk to in moments of desperation. He aids in her pursuit of solving the gravity equation by tricking Tom and keeping watch as she investigates her childhood bedroom. By the end of the film, he is also portrayed as a potential love interest for her.
Lois
Lois is Tom's wife, whose symptoms of illness Tom ignores. She appears well-meaning, but is also burdened by the loss of her first son and unsure how to handle the future of her family.
Coop
Coop is Tom's second and only living son. He is well-mannered and innocent, but subject to his father's intense denial when it becomes apparent that he's sick.
