Professor John Brand was a scientist and director of the remnants of NASA, as well the father of Amelia Brand. He asks former NASA pilot Joseph Cooper to join the expedition through the wormhole. He is played by actor Michael Caine.
Professor Brand spent years trying to solve gravity in hopes of allowing humanity to escape the Earth. To this effect, he established the basis for two possible solutions: Plan A, which required the gravity equation to be solved in order to allow humanity to live in colonies in space until they could find a habitable new world; and Plan B, to repopulate a viable world with fertilized embryos and begin humanity completely anew. At one point, he became acquainted with Joseph Cooper, who was a pilot and engineer for NASA.
When Cooper and his daughter Murphy find NASA's hidden base, Professor Brand encouraged Cooper to become the pilot for the Endurance as part of an interstellar reconnaissance mission to determine the viability of new worlds for humanity. The professor succeeds in persuading Cooper, providing assurance that Brand will solve the gravity equation that will allow humanity to survive in space to accomplish Plan A.
After the Endurance departs, Professor Brand continues to work for NASA to solve the gravity equation. He frequently sends messages to Amelia, reminding her of the importance of the Endurance's mission, though also to alleviate his own feelings of separation from his daughter. Roughly 25 years after sending the Endurance through the wormhole, Murphy Cooper has joined NASA and works with Professor Brand in order to find a solution to the gravity equation. When Murphy points out how they have repeated several iterations of their work, the professor becomes evasive, though he encourages Murph to continue. However, on his deathbed, he reveals their work on the gravity equation had been a sham. Brand confesses that he had determined the equation was incapable of solution without data from inside a singularity, but had not admitted it because the crew of the Endurance would not have left if they knew they were abandoning Earth. It is heavily implied that he believed that the "ends justified the means".
In the prologue segment of the original screenplay, John Brand is the young research assistant of the LIGO director Ansen. The film then flashes forward 50 years to show Cooper arriving at the NASA facility on Santa Cruz Island off the coast of Los Angeles, where Brand is advanced in age but also the director of the last remnants of NASA.