She has had minor parts in many shows, including playing Asia in four episodes of BBC comedy series Ideal, and two episodes of New Street Law, where she played a character named Susie Hardwick. She appeared in Heartbeat in 2002 and 2006 playing two different characters. Shows she has had a single appearance in include Life on Mars (The Stabbing), Holby City, The Bill, Coronation Street, Doctors and The Royal. She has also appeared in Children's Ward at her young ages. She also appeared in the film adaptation of Kevin Sampson's Awaydays, released in 2009.
Her partner is Shameless co-star, Ben Batt, who played Joe Pritchard. They met on the set in 2008 and shared numerous storylines together. In 2016, she gave birth to their son, Jack.
She is best known for playing Karen Maguire in Channel 4's popular comedy drama series, Shameless, and for appearing in all 11 series. She has also appeared in Life On Mars, Ideal and BBC Three's new "multi-platform sitcom" Trexx and Flipside. In October 2016, Atkinson joined the cast of BBC Scottish soap opera, River City, as Belinda Roberts, the ex cellmate of Amber Murdoch.
