Jeffrey 'Jeff' Hartigan is a man who was on Shane Schofield's research team while he was up in the Arctic.
Jeff Hartigan worked for ArmaCorp Systems, a weapons manufacturer, where he rose through to become a senior executive.
When the U.S. Marines insisted on cold-weather tests before agreeing to purchase their MX-18 Carbines, Hartigan and his assistant Chad accompanied a research team into the Arctic to perform the tests.
Hartigan was the one person that the other members of the team, particularly Shane Schofield, didn't get along with well. Whenever they weren't conducting tests, Hartigan spent most of the time in his own tent, sending Chad to get most of his meals. On one occassion where he did join the others for a meal, Hartigan was asked what he would do in the Nazi Dilemma conundrum, to which he stated he would sacrifice a crying baby to save the lives of himself and others, but was the odd one out as everyone else couldn't condone killing a child.
When Schofield received word that his team were needed to prevent a terrorist organisation from unleashing a deadly weapon from an old Soviet facility, he asked the civilians if they would come and help him. While Zack Weinberg and Emma Dawson joined them immediately, Hartigan stated that he and Chad would wait at camp while they ran off and got themselves killed. Chad, however, opted to go with Schofield. Schofield tried to reason with Hartigan that there was no reason to remain on his own, but Hartigan was adamant in avoiding the conflict. As Schofield's team was about to leave, Hartigan called them fools for taking such a huge risk.
Shortly after they left, Hartigan noticed an incoming aircraft, and was briefly fearful until he saw the U.S. Marine logos on the Osprey's flanks, and so, thinking they were friendly forces, went out to greet them. Unfortunately, it was not in fact a Marine force, but a unit from the Army of Thieves who had stolen the aircraft months earlier. As a result, Mako and his men quickly captured Hartigan and took him back to Dragon Island.
Hartigan was taken to the Dragon Island gasworks to be interrogated by the Thieves for intel on the rest of the research team. Hartigan was suspended from a forklift in a crude form of the strappado method, and during the torture he gave up the information they wanted. Suffering from both the torture and his uncomfortable position, Hartigan's shoulders eventually dislocated and he passed out.
When Schofield, Mother, and Baba were captured and brought to the gasworks, the Lord of Anarchy forced them to witness as Hartigan's head was encased in a wooded box and trapped rats inside it. Hartigan woke as the rats began attacking his face, but was helpless to do anything to defend himself as they ate his head, and his dying screams were broadcast across the island in the hope of forcing Zack and Emma to hand themselves in. When he was dead, Hartigan's body was dumped into the gasworks furnace.
As well as haughty and aloof, Hartigan looks down on anyone he doesn't see as an equal, which to him is just about everyone. He is also highly self-preservant, admitting he would kill a crying child to save his own life, and doesn't want any involvement in hopeless situations, calling anyone who takes extreme risks a fool.