Dennis Nedry was from Cambridge, Massachusetts. He worked at Integrated Computer Systems. As the novel describes him: "He was fat and sloppy, eating a candy bar, and there was sticky chocolate on his fingers, and flecks of aluminium foil on his shirt." As Project Supervisor of the Jurassic Park Project, he was first told to "design a module for record keeping". Nedry was never told everything, and was always working in the dark. He had become very annoyed with InGen; Hammond continually asked for things which hadn't been included in his original contract, and InGen demanded that they be done. When Nedry refused, lawsuits were threatened and letters were written to Nedry's other clients insinuating that he was unreliable. Nedry had no other choice but to return and carry out the extra work, but for no extra money.
It was this growing disgruntlement that made him receptive when Lewis Dodgson approached him with a plan to steal dinosaur embryos from InGen. Nedry accepted Dodgson's $1.5 million payoff. He recorded one of their conversations as insurance, in case Dodgson tried to rip him off. He then (or had already) coded Wht.Rbt.Obj, a trapdoor program in the code that shut off the security systems and the electrical fences, which would allow him to steal the embryos.
On the night that he had chosen to carry out his plan, Nedry discreetly activated his secret computer protocol, causing security systems to shut down all over the park. Doing it at this moment would leave Grant, Malcolm, Regis, Lex and Tim stranded in their tour vehicles outside the now unarmed Tyrannosaur paddock. He stole the embryos from the freezers, storing them in a specially adapted can of shaving foam given to him by Dodgson, then snuck away from the compound in a gas jeep, heading for the East Dock. Nedry hoped to be able to drive to the dock, deliver the embryos to Dodgson and then return to Jurassic Park and restore the security systems before he was missed. However, "[he] had thought of everything. Except this damned storm." The fierce storm that hit the island that night led to him veering off the road and encountering a dilophosaurus. The dinosaur blinded Nedry with its venomous saliva, ripped his stomach open, causing his intestines to spill out, and then crushed his head in its jaws.
Nedry's remains were later found by Muldoon and Gennaro, by now being devoured by a group of scavenging procompsognathus. Having witnessed all the death and chaos that Nedry's actions had caused at the park, Muldoon had little sympathy, remarking: "They blinded him, then ripped him down the middle. Not a nice way to go. Maybe there's justice in this world after all." When Gennaro asked what they should do with his body, Muldoon just stated they had more important things to worry about and left it where they found it.
His remains were presumed to be destroyed when the entire island was napalm bombed by the Costa Rican Air Force.