Kenneth Leith Halliwell was born on June 23, 1926, in Bebington, near Liverpool. He was very close to his mother when he was a child. This relationship made a big impact on his life. When he was just 11 years old, Kenneth saw his mother die from a wasp sting in their family home. This event affected him deeply.

He attended Wirral Grammar School, where he excelled in his studies and became a classics scholar. He completed his Higher School Certificate in 1943. In 1944, Kenneth was eligible for military service during World War II. However, he registered as a conscientious objector. He was exempted from military service under the condition that he would work as a coal miner.

After the war, Kenneth acted in plays for a time in Scotland and later returned to his hometown, Birkenhead, to continue his acting career. In 1949, his father died by suicide. Kenneth found his father's body the next morning. Despite this traumatic experience, he made a cup of tea and shaved before notifying anyone about the death.

Kenneth eventually moved to London to study drama at the Royal Academy of Dramatic Art (RADA), partly because he had inherited money from his family. In 1951, he met Joe Orton, a fellow student at RADA. They became partners and shared similar interests in acting and writing. Kenneth helped Joe develop his writing style, and together they created several unpublished works.

In January 1959, both men were involved in stealing and defacing public library books as a form of art. They were caught and served time in prison. Kenneth received a six-month sentence at HM Prison Ford in Sussex. The time that followed their release led to Joe Orton's success as a writer. However, this success put a strain on their relationship, which Kenneth found hard to accept. 

On 9 August 1967, Kenneth Halliwell killed Joe Orton by striking him nine times with a hammer. After the attack, Halliwell took sleeping pills, leading to his death as well. Their bodies were found the next day when a chauffeur came to pick Orton up for a meeting about his unproduced script, Up Against It.

Halliwell left a suicide note that mentioned Orton's diary. He suggested that reading it would explain his actions, particularly referring to Orton's comments about his own sexual experiences. The diary included references to Orton's sexual encounters in public places.