Kemsley's journey in stand-up comedy began in 2011, and within a short span of months, she emerged victorious in the Funny's Funny contest. Her remarkable talent and dedication earned her multiple accolades in 2012, including the Bath Comedy Festival New Act of the Year and the Brighton Comedy Festival New Act of the Year. The renowned comedian Rhod Gilbert also recognized her exceptional skills by naming her one of the Ten Must See Comics of 2012.
Kemsley's autobiographical solo show, Slutty Joan, received widespread acclaim from critics and was featured in The Guardian. In addition to her stand-up career, she co-hosts a popular podcast, Why Is Harriet Crying?, alongside fellow comedian Sunil Patel.
Kemsley has made numerous television appearances, including Sam Delaney's News Thing, Roast Battle, 8 Out of 10 Cats Does Countdown, and 8 Out of 10 Cats. In 2017, she and her then-fiancé Bobby Mair starred in a Viceland reality show, Bobby & Harriet Get Married, which documented their wedding ceremony, officiated by comedian Romesh Ranganathan.
As an actress, Kemsley has appeared in the film Bonobo and on television in Damned and Doctor Foster. She has also lent her voice to the video game Dark Souls II, where she portrayed Nashandra, the final boss.
