She made her screen debut in the 1987 independent film Rita, Sue and Bob Too, and subsequently worked consistently in television drama including roles in Coronation Street (1989–1990), Clocking Off (2000–2002) and The Amazing Mrs Pritchard (2006).
[1] Kate Muir, chief film critic at UK newspaper The Times, described the characters of Rita and Sue—two teenagers who both have a sexual affair with the older, married Bob (George Costigan)—"as raunchy, cheeky, unstoppable schoolgirls played with relish by Siobhan Finneran and Michelle Holmes.
[19][20] Subsequent roles in the early 21st century include the ITV1 Russell T Davies drama series Bob & Rose (2001), Sparkhouse (2002) –a modern re-telling of Wuthering Heights scripted by Sally Wainwright– and the two-part thriller Passer By (2004) starring James Nesbitt.
[19] In 2005, Finneran appeared as the female lead, Alice Holmes, in the original stage production of On the Shore of the Wide World at the Royal Exchange, Manchester.
Her character, Beverley Clarke is an established partner in a law firm who is inspired to launch a career in politics by her experience of the titular Ros Pritchard, and ultimately becomes an MP.
[24] A television correspondent at the Sunday Mirror described the character as a "fiercely protective lioness, humorous, straight-talking, and saucy" inclined to "let-it-all-hang-out" with a wardrobe comprising "skimpy, mutton-dressed-as-lamb outfits".
[25] Finneran found elements of the shoot embarrassing—including the requirement to be filmed in swimwear—[25] and one scene which involved her character "snogging" a young barman played by an actor in his early twenties.
[27] Finneran found filming her last scenes "heartbreaking" noting she was in "a terrible state" upon bidding farewell to co-stars and crew with whom she had forged a close relationship.
[28] In 2009, Finneran appeared as a main cast member in the three part ITV1 thriller Unforgiven as Izzie Ingram, a family lawyer who aids convicted murder Ruth Slater (Suranne Jones) track down her long lost sister.
[26] In 2013, Finneran starred in the second series of The Syndicate on BBC One, portraying Mandy, a hospital worker and domestic abuse victim who wins the national lottery with her colleagues.
[49] Also in 2013, Finneran portrayed Mrs Swift in The Selfish Giant an independent film inspired by both Oscar Wilde's short story of the same name and screenwriter and director Clio Barnard's personal experiences of the socially fragmented northern English underclass.
[56][57] Reviewing an episode of the second series, Jack Seale of The Guardian described Finneran as "brilliant" in her depiction of both Clare's "jittery vulnerability" and portrayal of "a snarling addict who has relapsed".
[57] In spite of the series' subject matter, Finneran claimed that as an inept cook, she found having to peel carrots and act simultaneously the hardest part of filming.
[65] Though correctly predicting that she would not win the award, Ben Lawrence of The Daily Telegraph identified her as who he felt to be the deserving winner praising the "subtle, unfurling power" of her depiction.
[68] In 2017, she portrayed real-life Detective Constable Christine Freeman in two-part drama The Moorside, a depiction of the 2008 disappearance of Shannon Matthews told from the perspective of the local community.
Quigley is an ambitious English career detective drafted in to investigate a serial killer and acts as a foil to the other protagonist, working mother and local woman DC Annie Redford (Laura Fraser).
[1] Finneran was keen to star in the series after reading the first three scripts and finding both her character and the small community setting intriguing, in addition to the prospect of working with a former Downton Abbey director (Brian Kelly) and Laura Fraser, whose acting she had long admired.
[71] Finneran based herself in Glasgow during the filming shoot and enjoyed "the buzz, the architecture, the social life",[1] describing the city as "one of my favourite places to ever work".
In the same year, she also played Elaine Pickford in A Confession, a TV dramatisation of a true story about the murder of two young women in England and the unusual events resulting from the capture of their killer.
Towards the end of the year, Finneran starred as Marie-Louise Dell, a prison chaplain, in the second series of Time, alongside Jodie Whittaker, Tamara Lawrance and Bella Ramsey.
On the role, Finneran told Radio Times: "I've just felt very privileged and very honoured to be part of this cast, although you can't say you've enjoyed the filming process because the content is really quite dense and brutal.