She rose to prominence as a member of the girl group Little Mix, which was formed and won the eighth series of, The X Factor UK.

[9] Before joining Little Mix, Pinnock worked as a waitress at Pizza Hut and used to post her music on MySpace and Facebook.

[10][11] Her early experience of organised singing came when she joined a youth club and choir then run by Jay Blades, who later became a trustee of her charity The Black Fund, which she founded in 2021.

[15] After she failed the first bootcamp challenge, she was placed in a three-piece group named "Orion" alongside Jade Thirlwall.

[27] That same month, she made her acting debut in the film Boxing Day, which she also recorded original music for.

[34] In March 2023, Pinnock uploaded a cover of "Weak" by American R&B trio SWV onto YouTube.

[40] She was featured on the song "Running Away" from Jon Batiste's album World Music Radio, released on 18 August 2023.

In October she was part of the BBC's Live Lounge line up and performed a cover version of "Paint the Town Red" by Doja Cat.

[50] It was preceded by the lead single "Stealin' Love", where that same month she performed her first headline show in London and at Rock in Rio in Lisbon.

[52] Pinnock has been in a relationship with professional footballer Andre Gray since 2016, after the pair met in Marbella.

[59] In February 2017, while performing with Little Mix as an opening act for Ariana Grande’s Dangerous Woman Tour, she suffered a burn backstage at one of their gigs.

[61] She co-founded her own swimwear range in April 2019, titled In'A'Seashell, in partnership with her friend Gabrielle Urquhart.

Pinnock is noted for her social justice advocacy; she speaks on issues including the Black Lives Matter movement, racial equality, colorism, feminism, and racism in the UK.

Early into her career, she refrained from discussing about these subjects over fears she would offend people and lose fans.

[70] In an interview with Glamour magazine, she spoke about her experiences with race and how she felt "invisible" for the first three years as the only black girl in Little Mix, while at the same time acknowledging her own privilege as a light-skinned, mixed-race woman.

My reality is constantly feeling like I have to work 10 times harder and longer to mark my place in the group, because my talent alone isn't enough.

[73] She also attended the Black Lives Matter protests in London, and she has spoken out about the murders of African-Americans George Floyd and Breonna Taylor by American police.

[74] In 2019, Pinnock (who is also known for her charity work), as well as other British celebrities, climbed Mount Kilimanjaro to raise funds for Comic Relief's Red Nose Day.

[76][77] In 2022, the charity co-funded two scholarships for young creative black leaders to expand their visions in Tokyo.

[78] In July 2023, Pinnock was awarded an honorary doctorate from Buckinghamshire New University in recognition of her anti-racism and racial equality work.