Marty is introduced alongside fellow student nurse Jade Lovall (Gabriella Leon) and writers paired them as a double act tackling their final university placement in the emergency department (ED).

Television critics and viewers alike spoke positively about the character, with Helen Daly from the Radio Times calling him her "favourite nurse".

Marty's friendship with Jade received a more mixed response; Sue Haasler of the Metro thought they made "an excellent double act" but disliked them being placed at odds.

On 1 August 2018, Sophie Dainty, writing for entertainment website Digital Spy, reported that actor Shaheen Jafargholi had joined the cast of Casualty as new nurse Marty Kirkby.

[7] Jafargholi explained that he spends a lot of time researching the terminology to understand it better,[8] and spoke to his mother, who works in a hospital, for advice on how to make the dialogue appear "natural" and "smooth".

[4] Jafargholi found that he could relate to co-star Maddy Hill, who portrays Ruby Spark, as she appeared on EastEnders before joining Casualty like him.

It might have been the thought of helping someone that made him daydream of wearing scrubs, but it was most likely the pull of working with other sassy nurses that lived off endless cups of tea and had an encyclopaedic knowledge of trashy telly.

Despite his blunt bedside manner, which some patients dislike about him, he has "flawless" clinical skills and technical ability, which establish him as a perfect fit for his job.

[8] The character's fictional backstory states that he decided to become a nurse at a young age and his ambition to achieve this set him apart from his peers at school.

Jafargholi told Sarah Ellis of Inside Soap that Marty likes Connie's vigour and personality and sees her as "a goddess", but often forgets that she is his boss.

[20] Inside Soap's 2019 preview for Casualty revealed that Robyn would discover that Marty has been claiming that he is Charlotte's dad in upcoming episodes.

[22] Robyn and Joshua discovering the truth coincides with a bad day for Marty as he lets down Louise with work and paramedics Iain Dean (Michael Stevenson) and Ruby Spark (Maddy Hill) eject him from the ambulance for his poor attitude.

[8] Simon Harper, the show's executive producer, thought they made a "brilliant, comic partnership",[25] and Raffety opined that Marty and Jade would bring "a whirlwind of life and fun" to the ED.

[9] Kian Madani (Ramin Karimloo) was introduced to Casualty's spinoff series, Holby City, in April 2019 and in his character biography, he was established as Marty's cousin.

[38] Jade is upset that Marty has not told her about his past and when his father, Graham Kirkby (Philip Wright), calls, she invites him to the award ceremony.

[47] Writers took Marty on a lonely "path of self-destruction" as he begins to have sex with strangers, taking drugs and getting drunk, following his father's rejection.

The suggestion was made by This Morning's resident doctor, Ranj Singh, who asked Harper if the drama could feature them as a reflection on the NHS, who use the badges as a message of inclusion.

[52] Writers created a turning point in the story when Marty discovers his casual sex and drug taking has put him at risk of contracting HIV.

Marty sees the experience as "a much-needed wake-up call" and arranges an appointment at the local sexual health clinic, before deciding not to prioritise partying over friends.

Kate Oates, the Head of Continuing Drama at BBC Studios, expressed her pride at the episode and thought that viewers would be "delighted to watch the never-before-seen moments".

[57] The episode features Marty being tested for HIV and addressing his issues with drugs and partying, before arriving for chaotic shift as the ED deals with a lockdown following a chemical attack.

Marty blames charge nurse Jacob Masters (Charles Venn) for Robyn's death and in protest of the broken system, he and David resign from their jobs and leave Holby.

Harper explained that both casts would be featured "striving heroically against the odds in two episodes of pure, nail-biting, taut, emotional medical drama.

"[64] In the episodes, Marty works with consultants Dylan Keogh (William Beck) and Serena Campbell (Catherine Russell) to treat a patient.

In the sketch, Marty and other characters, including Connie, Charlie, Archie Hudson (Genesis Lynea) and Ethan Hardy (George Rainsford), ask viewers various medical questions.

[67] Plans for the crossover were announced in August 2019 by Holby City series producer Jane Wallbank, who explained that Marty's relationship with Kian would be explored.

[81] Radio Times critic Alison Graham called Marty and Jade the "two very annoying new nurses",[82] and thought they were examples of "abysmal" discipline towards the ED's staff.

"[87] Writing about the success of Casualty, Dainty named the introductions of Marty, Jade, Archie and Will Noble (Jack Nolan) as reasons behind it.

She commented, "Jade and Marty's arrivals also injected a much needed sense of fun in the show, which has acted as a refreshing break from some of the heavier stories".

[96] Susannah Alexander, writing for Digital Spy, noted that viewers were disappointed about the missing episode as they felt it was "important" to Marty's character development.