 |
| Who Is Kelly “Mad Dog” O’Connor in MobLand? Meet Colin Morgan, the Actor Behind the Character. |
Colin Morgan joins MobLand as Kelly “Mad Dog” O’Connor, an Irish crime boss whose arrival could spell serious trouble for the Harrigan family. Introduced in the eighth episode of the second season, Mad Dog enters the story following the death of his father, Medusa, and wastes little time making it clear that he intends to find those responsible. With Harry and the Harrigans already dealing with Kat McAllister and Frankie Cooper, the arrival of another dangerous enemy is hardly welcome news. Unfortunately for them, Maeve has once again managed to make an already complicated situation considerably worse.
The second season of Paramount+’s crime drama has kept the Harrigans under pressure, with their enemies seemingly multiplying every time they manage to deal with one problem. Kat McAllister has become a formidable opponent, using Frankie Cooper as her latest weapon against the family.
However, while Harry, Conrad and the others remain occupied with that increasingly difficult conflict, Maeve has been busy creating another mess across the Irish Sea. Her latest scheme involves Eddie, a dangerous assignment and a powerful crime family that is unlikely to accept what happened quietly.
The trouble begins when Maeve sends Eddie to Ireland with instructions to eliminate Medusa, one of the country's most influential crime bosses. Eddie is clearly not prepared for the assignment, and things quickly spiral out of control. His attempt to complete the job goes spectacularly wrong, leaving Harry to step in and rescue him and Gina. Harry eventually kills Medusa, bringing the immediate situation to an end but creating a much bigger problem for everyone involved.
Maeve later explains that Medusa was not someone she particularly wanted dead because of a personal disagreement. Instead, she saw an opportunity to test Eddie by making him target the biggest crime figure in the area. It was an ambitious way to measure the young Harrigan's abilities, although sending someone into a dangerous situation without properly considering the consequences seems to be becoming something of a family tradition.
Eddie fails Maeve's little test, but Medusa is dead regardless. That is where the real trouble begins. Killing a powerful crime boss is rarely the sort of decision that ends with everyone shaking hands and going home, particularly when the victim has people willing to avenge him.
Kelly O’Connor, better known as Mad Dog, is the consequence Maeve apparently anticipated. We first encounter him at his father's funeral, where he pours alcohol over the coffin and makes a promise to find the person responsible for the killing. It is not exactly the most peaceful funeral speech, but it establishes his intentions rather clearly.
Medusa's position in Ireland means his death is unlikely to go unanswered. His associates and family have every reason to demand revenge, and Mad Dog appears particularly determined to deliver it. What makes the situation worse is that Eddie seems completely unaware that Medusa had a son capable of turning his failed assignment into a much larger conflict. Maeve, meanwhile, knows precisely who she has brought into the picture.
Mad Dog's reputation is already enough to make him an intimidating addition to the series. He has reportedly killed several people and spent 20 years in prison before returning to the outside world. Now that he is free, his attention has turned towards finding his father's killers. Considering his nickname, it is probably safe to assume that negotiations will not be his preferred method of settling the matter.
His investigation soon produces an important clue. Mad Dog discovers footage showing Gina and Eddie inside the bar where Medusa made his final stop for a drink. That discovery gives him a possible lead and puts the Harrigans directly in his sights. With Eddie and Gina connected to the location, it is only a matter of time before his search takes him towards London.
That development could be particularly troublesome for Harry. He is already trying to keep the family together while dealing with Frankie and Kat's growing threat. Adding an unpredictable Irish crime boss to the situation creates another front that the Harrigans may struggle to control.
There is also the possibility that Mad Dog could eventually find common ground with Frankie. Both have reasons to target the Harrigans, even if their motivations are completely different. An alliance between them would be a serious development, leaving Harry to face two dangerous opponents rather than dealing with each problem separately. Whether the series takes that direction remains to be seen, but the possibility certainly makes Mad Dog's introduction more interesting.
Colin Morgan plays Kelly O’Connor, aka Mad Dog, in MobLand. The Northern Irish actor brings an impressive television, film and theatre background to the Paramount+ series. Many viewers will recognise him from his starring role as Merlin in BBC One's fantasy drama Merlin, which helped establish him as a familiar face among television audiences.
Morgan's acting career began long before his breakthrough television role. Raised in Northern Ireland, he developed an interest in performing at a young age, appearing in school productions of Cinderella and Peter Pan when he was just five years old. His enthusiasm for acting continued as he grew older, eventually leading him to join a local amateur dramatic society.
At 16, Morgan decided to take his ambitions more seriously. He studied drama at Belfast Institute of Further Education before continuing his training at the Royal Scottish Conservatoire in Glasgow. While still a student, he secured a professional stage role in the Young Vic Theatre production of Vernon God Little. It was an early opportunity to demonstrate his abilities in front of a professional audience.
His biggest career breakthrough arrived shortly after graduation when he landed the lead role in Merlin. The BBC fantasy series gave him the opportunity to carry a major television production and introduced his work to a much wider audience. Playing the young wizard for five seasons also established him as an actor capable of balancing humour, emotional moments and more serious dramatic material.
Morgan has since avoided being tied to one particular genre. His television credits include The Fall, Humans, The Crown, Trying, The Sandman, The Killing Kind and The Boy That Never Was. These projects have allowed him to explore different characters and storytelling styles, rather than simply repeating the type of performance that first made him famous.
His film career is equally varied. Morgan appeared in Kenneth Branagh's Oscar-winning film Belfast, alongside roles in The Testament of Youth, The Huntsman: Winter's War, Dead Shot and The Dead Don't Hurt. Each project has added another dimension to a career that has moved comfortably between independent productions and larger screen releases.
The actor has also maintained a strong connection with theatre. His stage work includes The Tempest at Shakespeare's Globe, Translations at the Royal National Theatre, A Number at the Bridge Theatre and Our Private Life at the Royal Court Theatre. His continued involvement in live performance reflects an interest in exploring different forms of storytelling rather than limiting himself to television and film.
Morgan has also expanded his creative interests beyond acting. In 2026, he released his coming-of-age novel, The Ballad of Ronan McCoy, adding published fiction to an already varied professional career.
His casting as Mad Dog gives him another opportunity to demonstrate his range. After playing the heroic Merlin for years, stepping into the role of an unpredictable crime boss is quite a change of direction. The contrast should be particularly appealing to viewers who have followed his career since the BBC fantasy drama.
Opinion: Colin Morgan's casting could be one of MobLand's most interesting additions
Colin Morgan is an intriguing choice for Mad Dog, largely because he does not immediately feel like the obvious casting option for another intimidating crime boss. That is precisely what makes the decision interesting. Audiences familiar with his work in Merlin may need a moment to adjust before accepting him as someone with such a dangerous reputation, but that contrast could work brilliantly. Mad Dog also arrives at a useful point in the story, when the Harrigans already have enough problems without another enemy turning up to demand attention.
More importantly, his connection to Medusa gives the conflict a personal dimension rather than making him another character who simply wants power. Maeve's involvement adds an extra layer of frustration because she appears to understand the consequences far better than Eddie does. If Morgan gets enough screen time to develop Mad Dog beyond his reputation, he could become one of the season's most memorable characters.
Mad Dog's arrival leaves the Harrigans facing another potentially dangerous chapter, and Harry may soon discover that dealing with Frankie and Kat is only part of his problem. Maeve's decision to send Eddie after Medusa has created consequences that could reach far beyond Ireland, particularly now that Kelly O'Connor has a clear reason to pursue revenge.
Colin Morgan's casting makes the introduction even more promising, especially given his experience playing very different characters throughout his career. Whether Mad Dog becomes Harry's next major enemy or finds an unexpected partner in Frankie's campaign remains an intriguing question. What do you think of Colin Morgan's transformation into Mad Dog, and could he become the Harrigans' most dangerous opponent yet?