Born and raised in Ireland,[1] Clark Pullen attended Newpark Comprehensive School and then studied drama at Trinity College, Dublin.

Shortly after graduating, in June 1997, she was cast in her most notable role as Mary Flaherty in the BBC soap opera EastEnders.

Playing the long-lost relative of Pauline Fowler (Wendy Richard), Clark Pullen remained in the role for 18 months until her departure in early 1999.

[2] After Albert Square, she appeared in ITV's big-budget costume drama Lady Audley's Secret, starred in Catherine Cookson's A Dinner of Herbs and featured alongside Sir Richard Attenborough and Jenny Agutter in the remake of the classic The Railway Children, all in 2000.

After leaving EastEnders she admitted to suffering from panic attacks and depression as she struggled to cope with the instant fame she received from being in such a high-profile show.