Steadman trained at the Oxford School of Drama. She made her screen debut playing Julia Bertram in ITV Drama's adaptation of Mansfield Park. She has since appeared in several television programmes including The Tudors, The Inbetweeners, Holby City, Law & Order: UK, Missing, Lewis, Fresh Meat, Quirke and played Nurse Angela Wilson opposite Jack Davenport in the ITV drama Breathless. In 2014 she played Kate in comedy series Trying Again and Mabel Lane Fox in Downton Abbey.