John Bristow is described as “rabbity in appearance, with a short upper lip that failed to conceal large front teeth; his colouring was sandy, and his eyes, judging by the thickness of his glasses, myopic; but his dark grey suit was beautifully tailored, and the shining ice-blue tie, the watch and the shoes all looked expensive.” The Cuckoo’s Calling, Part 1, Chapter 3.

John was adopted by Alec and Yvette Bristow. His adoptive brother, Charlie Bristow, who had been good friends with Cormoran Strike at Blakeyfield Prep School, died at the age of nine after falling off the edge of a quarry whilst holidaying in Wales with the family. Strike remembers John as being the “surly” older brother. Shortly after Charlie’s death, Yvette and Alec adopted Lula Landry, who was four years of age at the time. John was 15 when Lula was adopted and 11 years older than her.

John works for the family law firm, Landry, May, Patterson, and is a very wealthy man with a trust fund. “I’m a pretty rich man, Strike. Sorry to be crass about it, but there you are.” He started dating Alison Cresswell, who also works at the firm, shortly after Lula’s death.

On Monday, 29th March 2010, John goes to Strike’s office to hire him to reinvestigate the death of Lula Landry.

During this first meeting, John, with his expensive grey suit and Vacheron Constantin watch, makes Strike feel self-conscious about his extremely creased shirt. As John enters the inner office, Strike stands to show his full 6-foot, 3-inch height and attempts to give the impression that he is a man too busy to iron his shirts.

With Strike being in a bad place financially, having John Bristow as a client is extremely helpful. Strike names an exorbitant price for the first month of work, and asks for a quarter of the payment in cash; Bristow proceeds to count out fifty-pound notes in addition to the cheque.

Throughout the investigation, Strike and John have regular contact via phone; they also meet for lunch at the Serpentine Bar and Kitchen to discuss the progress of the case and for John to give Strike Lula’s laptop.

In the TV adaptation, John Bristow is portrayed by actor Leo Bill, who is friends with Cormoran Strike actor Tom Burke.