Wallace's first move onto the world stage occurred after the Blackout brought the world into a state of crisis, with stock markets crashing and food shortages prevalent. He pioneered advancements into genetically modified food, essentially bringing an end to the global food crisis, ending his reclusiveness, and allowing his company to expand on Earth and onto off-world Colonies.
Three years later, the bankrupt Tyrell Corporation was bought out by Wallace, indicating Wallace's desire to continue replicant development despite the prohibition of replicant technology after the Blackout.
Wallace began to modify genetic engineering to produce replicants that were not only superior in strength and agility compared to their human creators, but also loyal beyond question, bred to obey. These Nexus-9 replicants were made legal after Wallace convinced the magistrates of Los Angeles in 2036 by showing them a completely obedient male Nexus-9.
In 2049, the remains of Rachael, a Nexus-7 replicant who had given birth, were discovered by the Nexus-9 Blade Runner, K, who visited the Wallace Corporation's headquarters in search of Rachael's identity.
Wallace himself wanted to discover the secret to reproduction in replicants in order to support interstellar colonization, and to this end he sent his replicant assistant, Luv, to steal Rachael's remains from the LAPD headquarters and follow K to find Rachael's child.
The pursuit of K led to the information that the child's father was former Blade Runner Rick Deckard, who was living in exile in Las Vegas. Luv and her men captured Deckard and brought him before Wallace, who offered him a clone of Rachael as a reward for revealing what he knew. When Deckard refuses, Wallace ordered Luv to escort Deckard off-world to be tortured for information.
K intercepted Deckard's captors and killed Luv but was mortally injured in the fight. Unbeknownst to Wallace, K then staged Deckard's death to protect him from both Wallace and the replicants.
Niander Wallace was an extremely sophisticated and perceptive individual, possessing an incredibly high intellect and a calm demeanor.
Despite all of his sophistication, Wallace was determined to accomplish his goals regardless of the cost. For example, when a new replicant was born, he silenced her and says cynically; "happy birthday," as she suffered. Wallace later tortured Deckard after he was brought before him, showing Deckard a clone of Rachael. He was also not a man who gave up easily, as he stated before Luv that the child of Rachael was the key for the future, not to the future of the humanity, but to the replicants he willed to create. It could be shown how Luv was attempting to prove herself to her master by never giving up in accomplishing the task.
He had somewhat of a god complex, as he called the replicants he creates "angels," and stated that he was a father of millions.
Additionally, Wallace was shown to be a brilliant strategist, delegating and employing others, rather than getting his hands dirty. But despite his brilliance, he was frustrated by his inability to gift replicants the ability to reproduce naturally and was jealous of Tyrell's accomplishments achieving what he could not.
Behind the scenes
The role was originally written with musician and actor David Bowie in mind. Denis Villeneuve attempted to contact Bowie about the role just days prior to his death in January 2016. Villeneuve commented, "After that, I felt like David Bowie became my muse for this role, and I had to find someone with the same magnetism. I had to find a rock star."
Earlier versions of the script called for Wallace to have no eyes at all, only sockets, rather than simply being blind. For preparation, Leto worked with the Junior Blind of America and used Silicon Valley tech investors and inventors that he personally knew as examples of how Wallace would behave. During filming, he wore opaque contact lenses that made it impossible for him to see anything.