Sladen began working for the Liverpool Playhouse as an assistant stage manager. Her first acting debut was playing the part of a corpse. She was constantly giggling which didn't help her land more roles. While working at the playhouse she met and married Brian Miller.

Eventually she began acting in repertory work. She appeared in roles such as Desdemona in Othello and a barmaid in six episodes of Coronation Street. She also played a stand up comics wife in Take My Wife and a small part in the film Dream Racer as a bank secretary.

In 1981 former producer of Doctor Who Barry Letts cast her in the BBC Classics production of Gulliver in Lilliput.

Sladen offered and accepted the part of investigative journalist, Sarah Jane Smith. She stayed on Doctor Who for three and a half seasons. Years later, John Nathan-Turner the new director of Doctor Who asked her to return, she declined but agreed to a second offer of playing in the series K-9.

Sladen is now appearing in The Sarah Jane Adventures, a Doctor Who spin-off produced by BBC Wales for CBBC and created by Russell T. Davies. The program was nominated for a Royal Television Society award and has been renewed for a second twelve episode series in 2008. She is also set to appear in the final two-part story of Doctor Who's 2008 series.

1. Born: February 1, 1948
2. Birthplace: Liverpool, England
3. Married to Brian Miller
4. Daughter: Sadie Miller
5. Voted Best Guest Actress
6. Front page news when she left Doctor Who
7. Only companion to have met 6 of the Doctor's incarnations
8. Read two audio stories for The Sarah Jane Adventures
9. Daughter appeared in The Sarah Jane Adventures audio