After Casey was discharged from the Canadian Special Forces, he was recruited by the United Nations to join the international peacekeeping organization as a field agent.
During the Omnic Crisis, his father was drafted by the Canadian government to defend the Canadian boarder from the Detroit omnium. After a month of repelling the omnic assault, Richard died in an explosion on Ambassador Bridge. However, due to his father's heroic acts, Casey was inspired to join the military. Despite his mother wanting him to become an engineer, Casey decided to enlist in the Canadian Special Forces.
Casey was eventually contacted by Jean-François Whaley, the Canadian Ambassador of the United Nation, who valued his heroism during the Omnic Crisis and offered him a position in Overwatch. Campbell accepted the offer and was flown out the the Overwatch headquarters in Switzerland. He was greeted by Florio Galván, who gave Campbell his indoctrination as well as his formal training for future covert missions.
Casey is noted to be a fairly "laid-back" kind of guy, but knows when to get the job done. He can be perceived as ethically ambiguous at times, but he always strives to keep the people he cares about safe. He is infamous for being incredibly stubborn, always getting in arguments with his superiors. When he disagrees with the direct orders he's given, he opts out in favor of a different action.
Despite his seemingly uncooperative tendencies, he is able to work with people in finding a middle ground to which everyone is happy.
To be added.
- The character of Casey Campbell was created by Oogaman.
- Casey's soldier number: 67 is in reference to the Constitution Act, 1867 (then called the British North America Act, 1867), which united the three separate colonies of the Canada, Nova Scotia, and New Brunswick into a single Dominion within the British Empire called Canada.