She began her television career by playing Jasmine Thomas in the soap opera Emmerdale from 2005 to 2009, followed by a recurring role in the BBC school-based drama series Waterloo Road (2009).

Coleman's other film appearances include Neil Maskell's dark comedy Klokkenluider (2022), and Jamie Childs' thriller Jackdaw (2023).

[12][8][13] While at school, she was a member of the theatre company In Yer Space, with whom she performed in the play Crystal Clear at the Edinburgh Festival.

[12] She was offered a place to study English at the University of York, but turned it down in order to accept the role of Jasmine Thomas in the soap opera Emmerdale.

In May 2009, it was announced that Coleman would be joining BBC school-based drama series Waterloo Road, as "hard girl" Lindsay James.

[14][20] Coleman went back to England after being called for the role of Annie Desmond, in Julian Fellowes' four part mini-series Titanic.

[19][21] In December 2010, it was announced that Coleman would be playing Susan Brown in a BBC Four television adaptation of the John Braine novel Room at the Top.

[22][23] The adaptation was originally intended to air in April 2011, but this was cancelled due to a rights dispute between the production company and Braine's estate.

[24] That same year, Coleman was cast as Rosie in Stephen Poliakoff's original drama series Dancing on the Edge, which follows the fortunes of a black jazz band in the 1930s.

[29] Although originally announced as beginning her run as companion in the Christmas special in 2012, Coleman made a surprise appearance on 1 September 2012 in the first episode of the seventh series as Oswin Oswald, a guest character.

[30] Coleman subsequently debuted as a series regular in the Christmas special episode "The Snowmen" as Victorian governess and barmaid Clara Oswin Oswald.

In that episode, Coleman also played a third version of the character, a resident of twenty-first-century London simply named Clara Oswald.

[33] However, the ninth series was her last, as Coleman had decided to leave the show to take on a role as Queen Victoria in an ITV production.

[3][36] In 2015, Coleman was cast in ITV's eight-part drama following the reign of the British monarch and Empress of India, Queen Victoria.

[42] On 8 January 2018, Coleman was confirmed to play Joanna in the four-part BBC drama The Cry, an adaptation of the 2013 novel by Helen FitzGerald.

[49] On 11 May 2019, in an interview with Graham Norton on his BBC Radio 2 program, Coleman indicated her intent to return to Victoria for a fourth series should it be renewed by ITV, but stated that the show will be taking "a bit of a breather" before production resumes.

[50] In the same year 2019, Coleman was selected for the role of Marie-Andrée Leclerc in the Netflix and BBC drama The Serpent, a dramatisation of the life of convicted serial killer Charles Sobhraj.

[57] In May 2020, nine years after its original English release, Coleman reprised her role as Princess Melia Antiqua in the video game Xenoblade Chronicles: Definitive Edition, which features a brand new epilogue taking place after the main story.

[61] The series debuted on Netflix in August 2022, when it was revealed that Coleman was playing two roles in the film; the aforementioned version of Johanna and her present day descendant of the same name.

[75] Coleman has been involved with charity work in South Africa raising awareness of HIV with One To One Children's Fund, for which she is an ambassador.