Not much is known about Coughlin. He presumably originates from Ireland, and his experience in both combat and technology suggests that he might have a military or special forces background. He also claims to have been to three inaugurations.
Coughlin parachuted to the Westworld Mesa Hub, after Charlotte Hale had called them. He was met by Ashley Stubbs, whom Coughlin didn't even seem to notice at first. He ordered his men, such as Engels, to get their gear ready. He apparrently only wanted to meet Charlotte. He appeared to have little to no respect for any of the Westworld staff, whether it was Stubbs or the technicians. He even joked at the expense of Stubb's feminine first name.
He was later in the Control Room, where Technician Hawking told him about not being able to turn off the Hosts agressive behavior. Coughlin didn't seem to care and ordered Goldberg to hack the system. Charlotte Hale then entered the room, stating that Peter Abernathy was contained. Not wanting him left unguarded, Coughlin ordered one of his men guard the host. Goldberg then managed to get the map back online, which showed a train (used by Wyatt's gang as bomb), approaching the building.
Coughlin led the defense against Wyatt's gang and managed to take out several of the hostile hosts. He got into a scuffle with Teddy Flood, and managed to get the upper hand on him for a moment, before the host could turn tables and get on top. Teddy then bludgeoned Coughlin to death with his bare hands.
After his encounter with Teddy, Coughlin involves in a fight with him. Theodor manages to overpower him and bludgeons his head with bare hands.
Coughlin seemed to be very arrogant and comanding. He showed little to no respect to Westworld employees such as Stubbs or Hawking, seeing them as amateurs. He even dared to speak against Charlotte Hale, a member of the Delos Board, though didn't use as phallic language against her. He seemed to have a respect for his own subordinates, such as Engels and Goldberg.