Callard appeared on stage as Juliet at the age of eighteen in "Romeo and Juliet", directed by Judi Dench. She played Celia in the UK and US tour of a production of Shakespeare's "As You Like It", Rosalind being played by Rebecca Hall. After a four-year break, she returned in 2009 with a production of another Shakespeare play "Macbeth" at the Royal Exchange Theatre, Manchester, and in a guest-star role in an episode of the television series "Robin Hood". In 2011 she played the part of Ruth Walsh in the drama soap Coronation Street.