Diefenbaker is a wolf hybrid from coastal British Columbia. While posted at the Prince Rupert detachment in 1992, Constable Benton Fraser found himself in a dangerous situation and met the animal as he held on to an ice floe drifting along the shore. The man began speaking to the wolf out of sheer boredom, and Diefenbaker dove into the Prince Rupert sound's icy waters to save him. This resulted in the wolf's partial deafness after his eardrums burst from the cold. Fraser trained the animal and named him after Canada's 13th Prime Minister, John Diefenbaker. Diefenbaker became Fraser's faithful police dog and followed him across the North where he learned to read lips in both English and Inuktitut. Diefenbaker does not wear a collar and doesn't seem to be officially registered as a RCMP detection dog, but he is accepted and readily put to good use when needed by the Force.
Diefenbaker is very loyal to Fraser and although they occasionally give each other the cold shoulder, the wolf has accompanied Fraser to Chicago where, to the constable's despair, he has become much of a city dog, developing a taste for fast food and even has his own checking account, which Fraser is careful to never disturb.Diefenbaker has had several run-ins with animal control, but Detective Raymond Vecchio forged a "wolf permit" that would allow him to stay in the city. During his first months in Chicago, the wolf often stayed in Fraser's apartment with his minder Willie, a twelve-year-old purse snatcher, until he escaped and was almost put to sleep for not only biting an animal control officer but also Fraser. An illegal operation running from the animal control office was discovered, allowing Diefenbaker to save the lives of numerous other dogs, including the pups he fathered with a husky bitch named Maggie.
Diefenbaker is generally well-liked by women who tend to treat him and allow him to follow them around. He is quite fascinated with blonde women, in particular Doctor Esther Pearson, Luanne Russell and Fraser's half-sister Margaret MacKenzie.
Diefenbaker was portrayed by six similar-looking Canadian Husky dogs, Lincoln, Frankie (Pilot only), Chinook, Kerry-Ann, Draco and Cinder (Draco's sister who performed most of her brother's stunts). Actor Paul Gross believes that Diefenbaker is what made this television series successful, and his own character so attractive to women.