Zachary Mitchell was the eldest son of Karen and Scott Mitchell, and brother to Gray Mitchell. He was sent, alongside his brother, to Jurassic World while his parents attended to their divorce proceedings. Zach was distant with his family and would attempt to court women whenever the opportunity arose. Before the events that transpired during their stay on Isla Nublar, Zach had a rocky relationship with his younger brother and would often insult and berate him, leading to his mother remarking that “he can be so mean” when they are left alone.
During the first day of their visit to Jurassic World, Zach found the opportunity to break free from the watch of Zara Young, Claire Dearing’s personal assistant tasked with taking care of the brothers, while she was distracted by a phone call as they were visiting the Gentle Giants Petting Zoo. Soon after, the two got on board a Gyrosphere minutes before the ride was shut down. Instead of returning as instructed, Zach convinced his brother that it would be fine for them to stay out for a while longer. They were attacked by the Indominus Rex soon after Zach piloted the Gyrosphere into a restricted area. The boys escaped and ended up in the abandoned Visitor Center of the original Jurassic Park where they found and repaired a 1992 Jeep Sahara that they then drove to Main Street.
During the ensuing chaos caused by the escape of the Indominus Rex, Zach began to bond with his younger brother and would offer words of comfort regularly. After the failure of Victor Hoskin’s plan to utilize Owen Grady’s Velociraptors to destroy the Indominus Rex, the two brothers worked together to protect a Mobile Veterinary Unit that they were riding on from the rouge Velociraptors.
Zach was present during the Indominus Rex’s attack on Main Street and aided Owen in saving Gray from the Indominus’ grasp as it tore through a gift kiosk. After the destruction of the hybrid, Zach, among the others, was evacuated to Costa Rica where he was reunited with his parents.