Thornton started her eponymous jeans brand in October 2006[6] when she was 33 years old.[7] The first boutique was located on Draycott Avenue in Chelsea, and was followed by boutiques opened in Westfield, Belgravia and Guildford.[8][9] The DONNA IDA fashion brand was launched in 2012. Notable fans of the brand include Made in Chelsea regular Millie Mackintosh, who in 2012 did a photoshoot with Thornton.[10] In 2014, the Donna Ida brand expanded its denim offerings to include more low-rise jean options.[11]
In 2016, the designer collaborated with high street retailer Jaeger to launch a new denim collection.[1][12] In 2017, British Vogue covered her brand's expansion beyond denim clothing into a lifestyle brand that includes merchandise such as candles and nightwear.[13]