Dr. Newton Geiszler is a scientist and former K-Science officer of the Pan Pacific Defense Corps. During the end of the Kaiju Wars, Newton Geiszler was the first human to attempt a Drift with a Kaiju, triggering the circumstances that led to the first Double Event, as well as the solution to destroying the Breach in 2025. A decade following the end of the Kaiju War, Newton has left the Pan Pacific Defense Corps to work for Shao Industries. Behind the scenes, Newton, under the control of the Precursors, works to further their goals, alligning himself with their mission to colonize the Earth.
Newton was born January 19, 1990 to parents Monica Schwartz and Jacob Geiszler. Newton's father was a pianist and his mother was a opera singer. Newton was conceived during an affair between Monica and Jacob. Following his birth, he was left in the care of Jacob's family when Monica chose to pursue her career as a singer. Jacob and his brother Illia Geiszler raised Newton on their own.
Following the August 10, 2013 Kaiju attack in San Francisco, Newton begins written correspondence with Hermann Gottlieb. The two form a rapport over the next three years through their letters before finally meeting in 2017. Coming face to face with each other, Newton and Hermann take an immediate dislike toward each other and part ways.
Pan Pacific Defense Corps
Newton joins the Pan Pacific Defense Corps in 2016. Following his graduation from the Jaeger Academy, he is assigned to the K-Science division. As a Cryptozoologist, he studies and examines the biology of the Kaiju remains salvaged from Jaeger battles in order to determine their weaknesses and understand them better.
His fascination with the Kaiju grows in such a way that he is considered a "Kaiju Groupie" by some within his division. In 2020, Newton is assigned to the Hong Kong Shatterdome with his former pen-pal, Hermann Gottlieb. Following the gradual decline of the Jaeger Program and its eventual decommission by the United Nations, Newton and Hermann are all that remain of the K-Science Division when Stacker Pentecost rallies what remains of the organization to continue the fight against the Kaiju.
Following the re-recruitment of Raleigh Becket by Stacker Pentecost, Newton works in disharmony with Newton in the effort to discover a means that will help the PPDC defeat the Kaiju. During a debriefing with Herc Hansen and Stacker, Newton deduces that the Kaiju are cloned, their internal systems practically identical.
In order to prove his theory right, Newton suggests that he attempt a Drift with one of the Kaiju brains they procured. Stacker, however, denies his request, and chooses to go with Hermann's plan to attack the Breach with a thermonuclear bomb while the Breach was stabilized by the increased traffic. Not dissuaded by Stacker's orders, Newton creates a makeshift Pons system in the absence of Hermann, and proceeds to Drift with the brain of a dead Kaiju. The process overwhelms him and triggers a seizure from a neural overload that leaves him senseless.
Hermann discovers him on the lab floor and rushes to retrieve Stacker, reporting his actions to the commanding officer. When he recovers from the Drift, Newton manages to explain that the Kaiju operate through a hive mind controlled by masters that intend to colonize the Earth once the Kaiju have wiped out the human populace.
Stacker sends Newton out into Hong Kong City to find Hannibal Chau. When he happens upon his store, Kaiju Remedies, Chau is not interested in obtaining a Kaiju brain for Newton until he outright suggests that it's possible to Drift with the mind of a Kaiju. When Chau discovers that Newton succeeded in Drifting with a Kaiju brain, he kicks him out of his shop, leaving him to fend for himself in a public Anti-Kaiju Refuge. Newton's connection to the Kaiju draws Otachi to the public shelter and is nearly killed, but the intervention of Gipsy Danger draws the Kaiju away from the scientist.
Newton returns to Hannibal Chau's shop angry, and demands that Chau provide him with a Kaiju brain. Following the death of Otachi, Chau and his crew attempt to retrieve Otachi's brain, but their harvesting attempts are cut short by the emergence of a infant Otachi that swallows Chau and chokes itself to death with its own umbilical cord when it attempted to kill Newton.
Deciding to use the infant Kaiju's brain in his second attempt to Drift, Hermman decides to help Newton Drift with the Kaiju brain. The two are able to discern that Striker Eureka and Gipsy Danger would require a Kaiju's genetic material to enter the Breach successfully. Newton and Hermann relay the information to the Rangers quick enough for Raleigh and Mako Mori to enter Breach and destroy it using the Jaeger's self-destruct sequence.
Alliance with the Precursors
Some time following the end of the Kaiju Wars, Newton decides to leave the PPDC and goes into the private sector. Newton joins Liwen Shao's Shao Industries as Head of Research and Development, responsible for the construction of her Drone Jaegers.
Newton continues to Drift with the secondary brain of a Kaiju, and falls under the sway of the Precursors. Newton uses Liwen Shao's resources to build and create hybrids of Kaiju and Jaeger to further the efforts of the Precursors, still intent on colonizing Earth.
As a consequence of Shao Industries' highly automated nature, Newton is able to clone Kaiju DNA to recreate Kaiju organs. Newton is able to mass produce an army of drones without drawing the suspensions of Liwen. In addition, he covers his activities with the Kaiju brain by creating a false relationship with a woman named "Alice", whom he mentions often in conversation with others.
Pacific Rim: Uprising
When Liwen Shao presents her plans for the Drone Jaegers to the PPDC, Newton is approached by Hermann Gottlieb with a proposal to create propulsion fuel out of Kaiju blood. Newton rejects the idea, dangerous and unnecessary once Liwen's drones are approved, but invites Hermann to have dinner with him and Alice.
Following Obsidian Fury's attack on the PPDC council meeting in Sydney, Australia and the death of Sectary-General Mako Mori, Liwen is suspected of sabotaging the council meeting to get the Drone Jaegers approved. Hermann goes to Shao Industires and approaches Newton for help. Hermann tells Newton that he believes that Liwen Shao used his research to manufacture unmanned drones, twisting it to her own ends, but Newton doesn't believe him. The two are arrested by Shao's security team Newton and taken into an elevator. Inside, Hermann feigns a coughing fit long enough for he and Newton to knock the security team out and head for the R&D lab. Newton threatens everyone inside with a gun, scaring them out of the room.
Newton tells him that he has a way of shutting down the Drone Jaegers. Newton explains to Hermann, who expects him to deactivate the drones immediately, that he created a backdoor subroutine in the Drones to allow him access whenever he wanted.
Instead of shutting the drones down, however, Newton initiates a "Breach Protocol". Hermann then questions his decision and Newton reveals that he spent the last ten years working with the Precursors to "end the world". He attacks Hermann, preparing to strangle and kill him to ensure that no one would prevent the Precursors plans from being derailed.
When Liwen Shao arrives, she grabs Newton's discarded gun and tells Newton to release Hermann, saving him. Newton mocks Liwen's ignorance, saying that fooling her was easy because so much of her corporation was automated. Liwen attempts to shoot Newton, but Hermann misdirects her aim, allowing Newton to escape unharmed. Liwen orders security to kill Newton on sight if he refuses to cooperate with them.
Newton arrives in MegaTokyo to observe the destruction being caused by the Kaiju that managed to cross the breaches created during hybrid drone attacks. During the battle between the Kaiju and the remaining Jaegers, Newton releases hundreds of Rippers from the warehouses of Shao Industries MegaTokyo branch. The Rippers fuse the Kaiju into a larger, stronger Kaiju type that destroys every Jaeger, save Gipsy Avenger. 
Before the Mega-Kaiju departs from the city to make for Mount Fuji, it stops long enough to regard Newton before moving on. When the Mega-Kaiju is killed in a Kamikaze attack by Gipsy Avenger, Newton attempts to salvage the situation with a backup plan, only to be knocked out by Nathan Lambert.
Newton is arrested and detained. Within the cell, Newton appears to rant to no one that the Precursors still intend to attack Earth, and more Kaiju will come to wipe out humanity. However, Jake Pentecost enters his cell and tells him that the PPDC intend to invade the Anteverse and bring the fight to the Precursors.
Newton is an abrasive and obnoxious personality who often acts without considering the consequences of his actions for those around him. As a scientist, he is ruled by his fascination with the Kaiju, and the want to understand what motivates their behavior on a biological level. His poor social skills in most circumstances, consequently, alienate him from individuals within the PPDC personally affected by the destruction brought on by the Kaiju.
Newton's upbeat and casual attitude clashed often with Hermann Gottlieb's straitlaced and orderly personality. Newton's lack of boundaries made it necessary for Hermann to draw explicit lines of where he was allowed to interact with him. Despite their disagreements, Hermann and Newton are capable of working, and even trusting each other. Newton often acts without thinking, and his desire to understand the Kaiju creates the circumstance wherein the lives of those living in Hong Kong, his own included, were put at risk when the Precursors learned of the PPDC's intentions in 2025.
Newton leaves the PPDC and pursues financial security within Shao Industries after the end of the Kaiju Wars. Because of his repeated Drifts with the Kaiju brain he names "Alice", Newton falls under the control of the Precursors. He works under the cloak of deception, willing to do anything to ensure the success of their plan. In his arrogance, Newton presumes superiority over those unaware of his intentions with Shao Industries technology, and enjoys the thought of the destruction of the human race.
What little remains of Newton's less abrasive personality appears to remain intact somewhere in his mind. However, he is not strong enough to buck the conditioning of the Precursors. The Precursors appear able to use their hivemind connection with Newton to assume direct control and speak directly to those interfering with their plans when necessary. They openly declare Newton is not strong enough to defy them.
- Charlie Day and Burn Gorman were the first actors officially announced to return for Pacific Rim: Uprising.
- During the production of the Pacific Rim sequel under Guillermo del Toro, Newton Geiszler and Hermann Gottlieb were mislabeled as the leads of the sequel.
- The plot twist involving Newton's involvement with the Precursors is based on an early script concept by Guillermo del Toro, who suggested the information taken from Newton in the Drift could be used by the Precursors.