Karoline was born in Liverpool, UK, and trained as an actress before turning to writing in the late 1980s. Her first ever play was written at age fifteen: a loose adaptation of the life of Anne Boleyn, and performed by an ensemble cast of three; herself, her best friend, and her mother. The best part about it was the head-chopping noises. Her first professionally produced play was an adaptation of The Snow Queen for Orchard Theatre, in 1989. She was Artistic Director of Bootstrap Theatre for three seasons and organised the lunchtime festival of new writing at the Brewhouse Theatre in Taunton, from 1993-95. Her first full length play THE MYSTERIOUS MR LOVE was produced by Bill Kenwright in 1997 at the Comedy Theatre in the West End. It received its first US performance in 2000, at the Penguin Rep, in upstate New York. Since then it has seen successful productions at many different venues in Great Britain, the USA, Canada, Australia and Poland.

Her first book, IN THE SHADOW OF THE DREAMCHILD: THE MYTH & REALITY OF LEWIS CARROLL, was published by Peter Owen in 1999, and created a considerable controversy when it claimed that Carroll's biography was more myth than fact. An extended and updated version was published in 2009.

Her play TRYST premiered off-Broadway at the Promenade Theatre in 2006.