She was portrayed by Téa Leoni.
Amanda lived in Enid, Oklahoma and was married to Paul Kirby. They had a son, Eric, but overtime they grew apart, constantly bickering and being unable to agree on anything. Amanda eventually divorced Paul just over a year before the events of Jurassic Park III. Sometime afterwards, she had begun dating Ben Hildebrand.
Jurassic Park III
After Eric and Ben's disappearance on Isla Sorna, Amanda pretended to still be married to her ex-husband, posing as a millionaire thrill-seeker in order to trick Dr. Alan Grant - unaware he had only traveled to Isla Nublar - into accompanying them to Isla Sorna to act as a guide, hoping he would be able to help them find her son. Upon landing on the island, Amanda began using a megaphone to call out to Eric, despite Dr Grant's protests that this would attract too much attention. He was proved right when a Spinosaurus attacked the group moments later, attracted by Amanda's shouting. Amanda narrowly escaped with the rest of the group. Throughout the film, Amanda often argued with Paul and ignored Alan's advice against making loud noises, shouting for Eric in her desperation and also screaming in terror when they encountered predatory dinosaurs. She was distraught when the group discovered Ben's corpse, especially when she became tangled in Ben's parachute, causing her to temporarily run off. When Paul tried to comfort her, Amanda admitted that she was more concerned for Eric's welfare than Ben's death, as it meant that their son was now all alone on Isla Sorna. She was greatly relieved when she discovered that Eric was alive and they were reunited.
By the end of the ordeal, Amanda began taking Alan's advice more, becoming less impulsive. She also grew closer to her ex-husband again, with the two of them sharing some affectionate moments, including Amanda commenting on Paul losing weight and saying he "looks good" and Amanda embracing Paul after finding Ben's corpse. When confronted by the raptor pack from whom Billy had stolen eggs, the Alpha raptor approaches Amanda, believing she was the one who had taken them (this is never fully explained, though one theory is that the raptors believed Amanda to be the Alpha of her own 'pack', due to her being the only female). Amanda managed to stay calm, asking Paul to give her the eggs, which then returns to the raptors. After the raptors depart, Amanda, along with the others, tries to warn the man standing on the beach with the megaphone to stop, no doubt remembering her own experience with making too much noise. Shortly after, Amanda is rescued from the island by the navy.
It is implied that Amanda and Paul got back together after they were rescued, because her final line in the film is: "I darethem to nest in Enid, Oklahoma." She and Paul then smile at each other.