Buck Frobisher is a sergeant of the Royal Canadian Mounted Police. He served with Robert Fraser as his partner in the RCMP for many years, and was Fraser Sr.'s best friend. Constable Benton Fraser encounters Frobisher in Chicago in the fall of 1994 through his daughter Julie who is worried about him. Frobisher is running from an old enemy, but in the end rises to the challenge of defending his dignity. Frobisher reappears later, mainly in a comedic role, notably in his tendencies toward flatulence, and toward making overly-dramatic speeches.

In their youth, Buck Frobisher and Robert Fraser both fell in love with Caroline Pinsent. It was Fraser who won her heart after a shooting match, and while Frobisher seems not to have completely gotten over the loss, his friendship with Fraser did not diminish. On the contrary, the friendship with Fraser Sr. inspires him to form a strong connection with Benton Fraser, and may be what allows him to see Robert Fraser's ghost, who typically appears only to family members and bitter enemies.

The charming, gritty and comedic Frobisher was portrayed by the late Canadian actor Leslie Nielsen.