| Dylan Keogh | |
|---|---|
| Casualty character | |
 | |
| First appearance | "Only Human" 12 March 2011 |
| Portrayed by | William Beck |
| Spin-off appearances | Holby City (2012) "Unsafe Haven – Part 2" |
| Crossover appearances | Emmerdale (2021) |
| Duration | 2011–2012, 2014– |
| In-universe information | |
| Occupation | Consultant in emergency medicine prev. Clinical lead |
| Family | Brian Carroll (father) Rihanna Carroll (half-sister) |
| Spouse | Sam Nicholls (until 2012) |
Dylan Keogh is a fictional character from the BBC medical drama Casualty, played by William Beck. He first appeared in the twenty-fifth series episode "Only Human", broadcast on 12 March 2011. The character was introduced as a replacement for fellow emergency medicine doctor Ruth Winters (Georgia Taylor). Beck had briefly attended medical school before becoming an actor, and he felt the role was right for him. Dylan is a Consultant in emergency medicine and a member of Holby City Hospital's emergency department staff. Since the departure of Charlie Fairhead in 2024, Dylan has been the longest serving character on the show.
Upon joining the cast, Beck was told by the producers that Dylan should not smile. Beck felt that he understood where Dylan is coming from. Dylan enjoys his work and likes to take on the more unusual cases and medical mysteries. He lives alone on a house boat with his dog Dervla. During his time in the ED, Dylan has developed strong friendships with Zoe Hanna (Sunetra Sarker) and Lofty Chiltern (Lee Mead).
Dylan's estranged wife Sam Nicholls (Charlotte Salt) was introduced to the ED in late 2011. They have a troubled relationship, which deteriorates further once Sam files for divorce and it begins to affect their work. Dylan has hope that they might reconcile, until he learns Sam is dating Tom Kent (Oliver Coleman). The character departed the show in late 2012, after he struggles to be around Sam, whom he still loves. Two years later, in 2014, Beck reprised the role and admitted that he was relishing the chance to play Dylan again. Dylan briefly takes up the position of acting clinical lead and tries to improve standards in the ED, but he is challenged by the job's demands.
In August 2015, producers introduced Dylan's estranged father Brian (Matthew Marsh), which led to further exploration of his background. Dylan has a poor relationship with Brian and his mental health suffers when they clash. He is later diagnosed with obsessive–compulsive disorder. The show's story producer wanted to challenge the character with the condition and show how it affected him personally. Later storylines have seen the character accused of sexual harassment, bringing a refugee into the country illegally, and developing alcoholism.