Born in Australia, George “Digger” Harkness was sent as a young adult to the United States by his mother to escape his stepfather. Taking up a job demonstrating boomerangs for the Wiggins Game Company, Harkness became an expert at throwing the boomerang and took to pilfering and thievery, opposed by the Flash.
Secretly the illegitimate son of an American soldier and an Australian woman, Harkness was raised in poverty, during which time he developed great skill in making boomerangs, and in using them as weapons. As a young adult, he was hired as a performer and boomerang promoter by a toy company in America which was, unbeknownst to him, owned by his biological father.
Audiences ridiculed him and a resentful Harkness turned to using his boomerangs for crime.
He originally became Captain Boomerang as a mascot for a Toy Company and briefly pretended another man was impersonating him.
Although he lacked any actual superhuman abilities, he became a recurring enemy of the Flash, typically by devising altered boomerangs which could produce astonishing effects, and using them ruthlessly. He later became a staple member of The Rogues: a group of villains dedicated to opposing Flash (Barry Allen).
Later on, Harkness became a less-than-effective member of the Suicide Squad in exchange for being pardoned for his crimes. However, Captain Boomerang's grating personality and blatant racism caused considerable friction among his teammates, and he was considered to be a dangerous, vicious, cowardly and undependable member of the team—dysfunctional even by the Squad's standards.
- Captain Boomerang is an enemy in the FP: Flashtastic Voyage raid of the World of Flashpoint episode.
- He can be found walking around in Burnley, Gotham, often near the Amusement Mile.
- Captain Boomerang is a random speed force traveler during the Family Reunion operation.
- George Harkness first appeared in Flash #117 (December 1960)
- Captain Boomerang (George Harkness) and Captain Boomerang (Owen Mercer) are actually father and son.
- In spite of his deplorable personality and attitude, Harkness has a deep patriotism for his home country of Australia, though his countrymen do not care at all for him, and a tremendous fear of being laughed at.
- Members of the Suicide Squad refer to Harkness by the nickname "Boomerbutt".
- Harkness was responsible for the death of Robin's father, Jack Drake. Digger had been sent by Jean Loring to attack Jack Drake, only she double-crossed Digger and sent Drake a warning and a pistol to defend himself as well; defending the action by saying that Boomerang was hired because he was such an incompetent that Jack would only need to pull the trigger and he would be safe.
|Affiliates||Amanda Waller - Bane - Black Adam - Captain Boomerang (George Harkness) - Captain Boomerang (Owen Mercer) - Captain Cold - Deadshot - Doctor Light - Duchess - Harley Quinn - Killer Frost - King Shark - Mirror Master - Oracle - Parasite - Penguin - Poison Ivy - Power Girl - Solomon Grundy - Speedy - Steel - Superboy - Vixen|
|Adversaries||Batman - Lois Lane|
|Other||Chemo - Vicki Vale|
|Bombshell Belle Reve's Poster|
|Apparel||Expert Marksman - Punchline|
|Belle Reve Federal Penitentiary|
|PvE||Suicide Squad Training|
|PvP||Belle Reve Sanitarium|
|Checkmate - United States of America - Justice League of America - Justice Society of America|