Deyn's working life started at a fish and chip shop in Stubbins, Rossendale, where she was a part-time server at the age of 13. Even at an early age she had an eye for style and by 17 she had already had her head shaved. "I've had short hair since I was 13, and when I was 17, I had a skinhead." In 1999, she won the Rossendale Free Press "Face of '99" competition, aged just 16.
Vogue Paris described her as one of the top 30 Models of the 2000s.
In May 2007, she was featured on the cover of American Vogue, alongside Doutzen Kroes, Caroline Trentini, Raquel Zimmermann, Sasha Pivovarova, Jessica Stam, Coco Rocha, Hilary Rhoda, Chanel Iman and Lily Donaldson as "The World's Next Top Models." She has also been featured on the covers of: UK Vogue, the Observer Woman supplement, The Sunday Times Style, Pop, Grazia, Time, Style & Life, Vogue Italia and numerous other international publications.
In May 2008, Deyn was guest Editor of i-D magazine. The issue was devoted to her and includes articles written by and about Deyn, as well as interviews she conducted with fashion designers such as Vivienne Westwood. Deyn's was on one of the fourteen covers of V magazine autumn issue. Each cover employs a head shot of a famous model, either from new Models or established supermodels; it was photographed by Inez van Lamsweerde and Vinoodh Matadin.
In June 2009, the Daily Mirror reported that Deyn had quit modelling to spend more time with her then boyfriend, Singer-songwriter Miles Kane. The newspaper quoted a source as saying that modelling had started to bore Deyn and that she had hired an acting agent to pursue an acting career in British independent films.
In 2010, Deyn collaborated with her younger sister Emily to create a line of T-shirts and tank tops for high street chain Uniqlo.
In March 2011, Deyn appeared as an owl-bearing warrior in Woodkid's debut music video, "Iron".
Deyn was married to American actor Giovanni Ribisi from 2012 to 2015.
In 2013, Deyn played the lead role in Electricity, a film adaptation of the novel by Ray Robinson, about the journey of a young woman with epilepsy.
In 2015, she starred in fantasy-horror thriller film Patient Zero.
In August 2016, Deyn married hedge fund manager Joel McAndrew in New York.
In 2017, Deyn began filming Hard Sun, a pre-apocalyptic crime drama for the BBC at Hanstead Park in Bricket Wood, Hertfordshire.
She then moved to London, working in a fast-food restaurant during the day and a bar at night but admits: "It didn’t quite work."
