Sharon was born in 1967 in the Drumchapel district of Glasgow, Scotland. She is the eldest of five siblings, and when she was 10 years old her family moved to Fife - in the east coast of Scotland - where she attended Kinghorn Primary School and became the Kinghorn Gala Queen in her final year. She was later a pupil at Balwearie High School and at Kirkcaldy College (currently known as Adam Smith College) where she started her drama studies.
In her pursuit to become an actress, Sharon moved to London at the young age of 19 to enroll at the prestigious Mountview Academy of Performing Arts graduating in 1989.
She lives in north London with partner Dan and their two boys Zac and Leo.