Froggatt was born and brought up in the village of Littlebeck. Her parents, having run a corner shop, next started a rare breed sheep farm on a smallholding near Whitby. Froggatt initially joined a drama group in Scarborough and then left her family home at the age of 13 to attend the Redroofs Theatre School in Maidenhead, Berkshire. In 1996, Froggatt made her TV debut in the long-running ITV drama, The Bill, and shortly afterwards landed the role of teenage mother Zoe Tattersall in Coronation Street. She left the programme in 1998 when her character was written out.