Dr. Alan Grant is a dedicated paleontologist who prefers the dusty earth of excavation sites to corporate boardrooms. He studies dinosaur behavior and anatomy, relying on external grants to fund his pure scientific research. He agrees to visit Isla Nublar at John Hammond's request in exchange for a $60,000 consulting fee to support his future expeditions. Upon arriving at the island, his academic theories are entirely upended by the reality of living, breathing dinosaurs.

Ian Malcolm is an outspoken mathematician specializing in chaos theory. Originally hired as a consultant during the park's early design phase, he openly insists that Hammond's project is doomed to fail due to the inherent unpredictability of complex natural systems. He views the attempt to isolate and control prehistoric nature as arrogant and mathematically impossible.

John Hammond is the eccentric creator of Jurassic Park and the head of the InGen corporation. He possesses a childlike enthusiasm that masks a manipulative and profit-driven business sense. Determined to create the ultimate biological attraction for wealthy tourists, he dismisses all safety warnings, firmly believing his vast wealth can purchase control over nature.

Dr. Ellie Sattler is a vibrant and highly observant paleobotanist in her mid-twenties. She partners with Dr. Alan Grant on scientific expeditions and accompanies him to Isla Nublar. Her specialized knowledge of ancient plant life immediately alerts her to the careless and dangerous landscaping decisions made by the park's designers.

Dennis Nedry is a talented but deeply disgruntled computer programmer responsible for Jurassic Park's complex security systems. Furious over his compensation and Hammond's demanding management style, he formulates a selfish, rogue plan to sabotage the park's security grid. He acts as a corporate spy, disabling vital systems to steal viable dinosaur embryos for a competitor.

Tim Murphy is John Hammond's eleven-year-old grandson. He is an avid dinosaur enthusiast who has read multiple books on the subject and is thrilled at the prospect of experiencing the park firsthand. Bright and highly observant, he easily spots signs of danger and technical details that adults overlook.

Lex Murphy is John Hammond's eight-year-old granddaughter. Initially cynical and uninterested in dinosaurs, she carries a baseball glove and complains about the lack of normal recreational activities. Her initial annoyance masks a strong survival instinct when the environment turns hostile.

Robert Muldoon is the hard-nosed game warden at Jurassic Park. Originally from Kenya, he is accustomed to managing large, untamed predators like lions and rhinoceroses. He brings a practical and highly cautious perspective to the island's operations, frequently worrying about the intelligence and aggressive nature of the velociraptors.

Dr. Henry Wu is the brilliant molecular biologist responsible for cloning the park's dinosaurs. Hired straight out of graduate school by InGen, he views the prehistoric creatures primarily as technological achievements rather than living animals. He uses amphibian DNA to repair genetic sequences and constantly lobbies to create more docile "Versions" of the animals.

John Arnold is the chain-smoking chief engineer of Jurassic Park. With a background designing military missiles and Disney theme park attractions, he views the entire island as a massive, controllable machine. He relies heavily on computer automation to run the complex facility and dismisses mathematical warnings about system failure.

Donald Gennaro is a stocky, Armani-clad lawyer representing InGen's primary investors. Having originally helped Hammond secure funding with deceptive demonstrations, he travels to Isla Nublar to assess its safety after several worker fatalities. He is intensely focused on minimizing financial liability and threatens to dismantle the park if it proves unsafe.

Harding is the chief veterinarian at Jurassic Park, formerly a leading expert in avian care at the San Diego Zoo. He is an easygoing professional tasked with the unprecedented medical challenge of caring for prehistoric creatures. He relies heavily on his background with modern birds to diagnose the unfamiliar ailments affecting the dinosaur population.

Ed Regis is the anxious public relations manager for Jurassic Park. Tasked with managing the park's image and maintaining secrecy, he lies to doctors about the true cause of horrific worker injuries. He views himself as cool under pressure but becomes visibly terrified when assigned to chaperone Hammond's grandchildren on the park's inaugural tour.

Dodgson is the head genetic engineer for Biosyn, a direct corporate rival of InGen. Eager to catch up to Hammond's astonishing breakthroughs in cloning, he orchestrates a dangerous corporate espionage plot. He supplies an InGen employee with half a million dollars upfront and a disguised container to smuggle out viable dinosaur embryos.

Bobo Morris is an investigator for the Environmental Protection Agency. He tracks the purchase of high-tech genetic sequencing machines and giant generators by the Hammond Foundation, questioning academics about InGen's unmonitored activities in Costa Rica.

Alice Levin is an observant technician at Columbia University who examines the partial remains of an unidentified animal. She is the first scientist to openly suggest the creature looks remarkably like a dinosaur, prompting her to stubbornly contact experts despite her superior's dismissal.

Dr. Richard Stone is the practical head of a tropical disease laboratory. Highly skeptical of unusual theories, he flatly rejects the notion that the tissue sample could belong to a dinosaur, insisting the remains be stored in a freezer and ignored.

Dr. Roberta Carter, who goes by Bobbie, is a dedicated doctor at a rural Costa Rican clinic. She attempts to treat a young InGen worker brought in with horrific, fatal lacerations. Despite corporate cover stories, her medical expertise immediately tells her the injuries are the result of a vicious animal mauling.

Tina Bowman is a curious young girl vacationing with her family in a lush jungle resort. While exploring the beach and looking for local wildlife, she is approached and severely bitten by an unusual, bird-like lizard that walks on its hind legs.

Mike Bowman is a father taking his family on a tropical vacation. When his daughter is attacked by a mysterious creature on the beach, he quickly transports her to a local hospital to treat the rapidly swelling bites.

Ellen Bowman is a mother vacationing in Costa Rica. She secretly arranged the trip to secure affordable plastic surgery, but her plans are completely derailed when her daughter suffers a bizarre animal attack.

Marty Gutierrez is an American biologist working in Costa Rica. He initially identifies the creature that bit a young girl as a harmless basilisk lizard, but growing doubts and the discovery of infant attacks lead him to suspect a much larger biological mystery.

Daniel Ross is a cautious attorney at the law firm representing InGen. Deeply concerned by reports of worker deaths and the immense secrecy surrounding John Hammond's remote island, he instructs his colleague to assess the situation aggressively.