Owen Hunt is Chief of Surgery and Head of Trauma at Grey Sloan Memorial Hospital (formerly Seattle Grace Mercy West Hospital). He previously served in the army, but was honorably discharged due to the death of his entire platoon, and was later a large factor in George O'Malley's decision to enlist. He was romantically involved with Cristina Yang, but the two were currently apart, due to their different opinions on having family. Before Cristina left for Zurich they got briefly together again.

Owen is a very skillful and innovative doctor, hardworking, quick-witted and relentless. He has respect for his patients and demands the same from his residents and colleagues. His training as an army trauma surgeon allows him to use even the most simple household objects (e.g. a ballpoint pen) as surgical tools, and he is known to improvise when facing a lack of proper equipment. As a surgeon he works hard, even working three days straight, and in addition to taking care of the ER he also takes some general surgery cases every now and then. According to him, he became a doctor because he wanted to help people, and because no one could read his handwriting.

He attended Harvard and completed his residency in general surgery at Maryland Shock Trauma Center, making quite a name for himself there, according to Richard Webber. Shortly after 9/11, He enlisted in the army and became an army trauma surgeon. During his time in Iraq, he saw and experienced terrible things that would haunt him for a long time, such as seeing many of his friends and colleagues get shot or blown to pieces. He stayed in Iraq until one day his entire platoon of 19 was killed in an RPG ambush, leaving him as the sole survivor, and he was honorably discharged from the army. He then returned to Seattle and took up the post of Head of Trauma Surgery at Seattle Grace Hospital, restoring it to a level one trauma center.

At first, Owen had some trouble with making a transition from Army field medicine to civilian traumas, and his aggressive course of treatment and unwillingness to ask help from the other attendings was frowned upon by Derek Shepherd and Mark Sloan, who quickly started calling him names, such as "Rambo" and "Meatballer". However, Owen quickly adjusted to working in a civilian hospital and learned to page help instead of doing everything himself. His surgical skills soon impressed his colleagues, and George described them as "amazing", while Callie described Owen as "meticulous."

Over the next few months, Owen also started teaching residents in trauma and how to work quickly and efficiently in hard circumstances. His teaching methods were rather unusual and slightly unorthodox, for example, teaching his residents how to work with "live tissue" by stabbing six pigs and asking his residents to save them. He also taught his residents to respect their patients and trust more on their own evaluation instead of always relying on attendings.

During Derek's depressed period, Hunt revealed as a second year resident, he lost the parents of three children, and it haunts him everyday. When Derek commented that he expected a story about Iraq, Owen stated that he doesn't talk about Iraq. He did, however, tell Cristina one story about Iraq: how he had once laid still on top of a severely mangled bomb victim for two hours, preventing him from bleeding to death, something that he described as his "best and worst" surgery.

Owen's level-headedness and professionalism caught the eye of Chief Webber, and Owen soon became his right hand man, Webber putting him in charge of selecting both the winner of the resident solo-surgery and the chief resident. He also placed Owen in charge whenever the hospital faced crisis or emergency, given his training in working under pressure.

After Webber stepped down as Chief of Surgery after taking the blame for Meredith's tampering of the drug trial, he asked Owen to take over his position. Owen accepted the offer and became the new Chief of Surgery at Seattle Grace Mercy West, much to the surprise of his colleagues. At first Owen was struggling with his new position, feeling deskbound, and it didn't take him long to start drinking, so Derek took him to his construction site and adviced him to improvise. The next day Owen gave up his office, saying that from now on, his office would be wherever he was. Using a tablet-like device to manage the hospital, he was able to carry his office with him and free himself to work in the Pit and do surgeries.

Owen's position as the Chief of Surgery was threatened, however, during the aftermath of the lawsuit. After doing everything in his power to prevent the hospital from going under, he and the plane crash survivors were able to buy the hospital with the help of the Harper Avery Foundation, and the doctors were nominated as the new Board of Directors. In their first meeting, Jackson Avery brought up the Foundation's recommendation to replace Owen Hunt as Chief of Surgery in order to "increase the morale". This recommendation was met with utter disgust by the other board members, but when Owen heard of the recommendation from Cristina, he was enraged and after an argument between him, Avery and Shepherd decided to quit, leaving the hospital in chaos. Cristina then made Derek go apologize to him, and he agreed to return as Chief of Surgery if the ER would be reopened, a condition to which everyone agreed.