John King was born in Kent, England. He has two sons, Peter and Simon, and is married to Joy. He has mainly worked in insurance, and is an active member of a local church.

John has always had a keen interest in humour. He initially ventured into Instagram (and Facebook) as Cartoon Headcase, where his cartoons have continued to gain a large following.

John also publishes on Medium.com, and is contributor to many online publications within it. He is also editor of the Medium publication 'Cartoon Headcase'.

His humour covers autobiography, life observations, ironies, plays on words and the downright bizarre. The Cartoon Headcase mission statement is 'a smile on every face and a book in every bathroom'. This has led to the publishing of his books: 'Cartoon Headcase: Cartoons To Make You Happy', 'Cartoon Headcase: Making The Whole World Laugh', 'Cartoon Headcase: The Science Of Humour', 'Cartoon Headcase: Mexican Wave Of Laughter' and the themed compilation: 'Cartoon Headcase: Christmas Cracker'. Several more are to be released in 2020.