Sergeant O'Flaherty was an Irish-American member of the New York Police Department, appearing in the 1987 TV series episode "The Great Boldini".
Sergeant O'Flaherty was under the command of Lieutenant Fronski. The two of them, along with other officers, worked the case to recover the Tortellini Emerald. Although Fronski immediately fingered the Ninja Turtles as the culprits, O'Flaherty wondered what they'd need with an emerald when they had gold, somehow thinking they were leprechauns.
Later, after the Turtles escaped, O'Flaherty attempted to arrest them. April and Leonardo convinced the Sergeant to let them bring in the real thieves, with April giving him a kiss on the cheek in thanks.
Zach, Caitlin, and the Turtles captured the real thieves, Don Turtelli and his cousin the Great Boldini. On April's TV interview with him, O'Flaherty thanked the "Teenage Mutant Ninja Leprechauns" for their assistance in the capture.