Captain Boomerang is an Australian bank robber, gaining his nickname for his skilled use of boomerangs during his heists. After robbing every bank in Australia at least once, he went to America for new targets. Unfortunately for him, during one of these heists (after he used a boomerang to knock out his accomplice) he was taken down by the Flash.
After his capture, he was charged guilty in 54 counts of aggravated assault and 98 counts of first-degree burglary. He was sentenced to a triple-life sentence.
When the squad is activated, Boomerang is injected with a nanite explosive into his neck and transported to Midway City inside a sack. After the sack is opened, Boomerang immediately attacks the nearest guard but is restrained at once. He equips himself with a set of blades and a stuffed pink unicorn before the squad sets out. When El Diablo states that all of them are walking straight into their deaths, Boomerang ignores it and makes fun of Diablo's tattoos, much to the amusement of Killer Croc.
After the helicopter has crashed in Midway City, Boomerang convinces fellow team member Slipknot that the talk about bombs implanted inside their necks is merely minded games and the two decide to bolt together. Harkness draws one of his boomerangs but is immediately detained by Katana. Slipknot, however, uses his ropes to escape and Flagg immediately detonates the bomb inside his neck. After Slipknot's death, Boomerang realizes how close he came to death right now.
After the group is forced to battle some of the Enchantress' henchmen, Boomerang confronts El Diablo for not fighting with them. Diablo states that it is better this way, as he does not want to use his powers ever again. Although Boomerang provokes the 'fire bloke', Diablo stays calm. Boomerang also attempts to steal a wristwatch from one of the beasts they killed, causing them to realize that they were fighting inhabitants of Midway City all along.
After they have entered the building where they are supposed to meet their target, Boomerang comments on the brief calm, calling their progress easy and sarcastically referring to their mission as a walk in the park. Deadshot is annoyed by his constant quips. Inside, the group is attacked by more of the hostiles. Boomerang is stabbed in the chest but remains unharmed due to his body armor.
When they arrive at the target location, they are shocked to find out that the person they are supposed to extract is Waller herself. Boomerang speaks up and advises to kill both Flagg and Waller to prevent going back to prison after the mission is done. However, Waller holds up her phone to remind them that she still has the power to explode any of them.
When their extract helicopter (revealed to be hijacked by the Joker) escapes with Harley Quinn, Waller orders Deadshot to kill her. When Deadshot deliberately misses Harley, Boomerang congratulates him on making the right choice. When Harley rejoins the team later, Boomerang welcomes her back and hands her baseball bat.
After Waller's escape chopper has been shot down, the rest of the squads heads into a nearby bar. There, the members start arguing, starting when Boomerang calls Harley nice to look at but ugly on the inside. The fight is broken up when Flagg enters the bar as well, smashing his wrist monitor and thus destroying his device allowing him to explode the nanites. He reveals to the squad that he has to stop the Enchantress but that all of them are free to go. Boomerang storms out of the bar immediately. However, he eventually rejoins the group.
Shortly before the battle, Boomerang tries to convince Katana that the two of them need to have a drink someday. When the battle erupts, Boomerang is almost killed by Incubus but is saved just in time by Katana. When the squad members battle the Enchantress, Boomerang is pinned down by her and almost killed but is once more saved by a squad member, this time by Killer Croc.
After the Enchantress is defeated, Waller turns up to bring the squad back to prison. Although Boomerang furiously demands to be released, Waller forces him to stand down by threatening him with the nanite bomb in his neck. Boomerang is subsequently brought back to Belle Reve and Pinky confiscated from him once again, still angrily ranting and demanding to be freed, to no avail.
Birds of Prey
Although he does not physically appear in the film, Boomerang is seen on a photograph in the Gotham City Police Department building during Harley Quinn's attack on it in order to find and capture Cassandra Cain for Roman Sionis, with Harley remarking "Hey, I know that guy" upon seeing it.