Finn was created to replace Antonia Thomas and Iwan Rheon, who played Alisha Daniels and Simon Bellamy, after they departed the show.
[8] Finn arrives for his first day of community service where he meets fellow young offender Jess (Karla Crome).
Using her X-ray vision, Jess sees that Rudy has Curtis Donovan (Nathan Stewart-Jarrett) locked inside a freezer and they then help him escape.
[11] A week later, Finn continues the search for his father by interviewing several members of a group photo taken with his mother on the night he was apparently conceived.
After a few knock backs and finding out his mother was referred to through her school years as 'Anal Mary', he finally found his father and also discovered he had a half-sister, Grace, as well.
Feeling uncomfortable he tries to reject Greg's advances, and ends up accidentally using his telekinesis to throw him over a flight of stairs.
At the party marking the one year anniversary of the Storm, Finn finds out about Rudy and Jess' relationship, and becomes infuriated as he refuses to forgive either of them.
After Sarah, Alex's new love interest, gains the Satanic Conversion power from the first episode of the series, she converts him.
In the final episode of series 5 when Jess jumps forward in time one year she finds out that Finn has become a trainee probation worker, teaming up with Greg to discipline young offenders.
Finn's story arc ends with him becoming friends with Rudy and Jess again, and accepting that he should become a superhero with the rest of the gang.
Writing for The Independent, Neela Debanth said Finn is "a wide-eyed, naïve manchild with an odd sense of humour and an ineptitude for telekinesis".
Debnath felt that Overman "is clearly trying to avoid replicating personalities in order to make sure that Jess and Finn are not seen as replacements but characters in their own right.
[13] Morgan Jeffrey of Digital Spy said that Finn is "not so much a motor-mouth as someone who suffers perpetually from 'word vomit', coming out with all manner of bizarre and dark ramblings in his efforts to impress".
Jeffrey added that the show may have begun to find itself with "the intriguing reveal that Finn - previously a bit of a one-note buffoon - may have quite the dark side".
[14] Jordan Farley of SFX said the episode "actively encourages us to dislike, or at least be put off by, these characters" such as when "Finn tells some reprehensible fibs".
He’s a little bit like a cowardly, scouse version of Heath Ledger’s Joker, constantly telling tall tales about his past, but whatever we learn is coloured by the reveal at the end of the episode".
He went on to say that his efforts to escape Sadie's influence "may have been a little extreme to say the least, but you can't help but sympathise with the poor lad's plight once you learn the truth and his bizarro relationship starts to unravel".
Jeffrey commented that Finn begins to "feel a little more real" during the second episode of the fourth series which allows "McMullen's cheeky Scouser [...] more room to breath".
Jeffrey added that the "new group dynamic also feels like it's taking shape, with Finn in particular having already found his role as the gang's new punching bag".
She criticised the episode's attempts to "pull at the audience’s heartstrings" by using Finn's relationship with Sadie as she felt it "just fell flat".
[20] Catriona Wightman of Digital Spy felt that Finn's storyline with his father's ex-girlfriend Lisa is more "interesting - or at least more strange".
She felt the storyline was worth it as it led to "the heartbreaking scene as Finn discovers that his dad is actually not his biological father - making him even more lovable.
And the story also pushes forward the cute blossoming romance between Jess and Finn, making their feelings for each other more clear".