Daughter of the television writer Pat Dunlop, she began as a child actress in the seventies featuring in a BBC version of the classic A Little Princess and as Lydia Holly in the ITV adaptation of South Riding.
Her transition to adult roles began by playing Lizzie Hexham in a BBC version of Charles Dickens' Our Mutual Friend in 1976 and featuring in the very first series of the long-running hospital drama Angels.
She was cast alongside Diana Rigg and Elizabeth Taylor in the 1977 film version of Stephen Sondheim's A Little Night Music and appeared in Roman Polanski's Tess in 1979. In 1980, she played Nora, the nurse who is at first terrified by The Elephant Man and then befriends John Hurt's character in David Lynch's 1980 Oscar winning film.
Throughout this time and indeed throughout her career, she has regularly appeared on British TV including Murder Most English in 1977, and two guest appearances in Doctor Who - Frontios in 1984 and The Happiness Patrol in 1988. In the 1990s she starred in the long running BBC sitcom May to December as Zoe Callender alongside screen husband Anton Rodgers.
In 1995, she starred in the two part Gurinder Chadha directed drama Rich Deceiver as Ellie Freeman, a Liverpudlian housewife who secretly wins the pools and uses the money to covertly help her husband's career. She also starred in the ITV series Wokenwell (1997) and appeared in a long-running series of TV commercials for Kleenex directed by Mike Leigh.
In 1998, she made a guest appearance as Veronica Tate in the ITV police drama series The Bill.
In 2000, Lesley joined the cast of the ITV series Where the Heart Is playing Anna Kirkwall.
She is currently playing Brenda Walker in the ITV soap opera Emmerdale.
Lesley Dunlop is the mother of actress Daisy Dunlop. She also has another daughter called Rosie.
She is in a relationship with Chris Chittell who plays Eric Pollard in the ITV soap opera Emmerdale.