[1] Grey first appears in the second Outlander novel Dragonfly in Amber (1992) as a 16-year-old English soldier who chances upon Jamie and Claire Fraser on the eve of the Battle of Prestonpans.

[2][3] Using the threat of harm to Claire, Jamie tricks Grey into revealing information about the nearby British forces, and spares the boy's life.

The character makes subsequent appearances in Drums of Autumn (1997), A Breath of Snow and Ashes (2005), An Echo in the Bone (2009), and Written in My Own Heart's Blood (2014), as well as in The Fiery Cross (2001) by way of a series of letters to Jamie and his family.

Outlander, a television adaptation of Gabaldon's series, premiered on Starz in August 2014,[5][6] with each season based on a novel in the sequence.

[2][3][10][11] Kennedy portrays a young Grey in the 2016 season two episode "Je Suis Prest", adapting the character's appearance in Dragonfly in Amber.

[12] In August 2016, Starz announced that David Berry had been cast as the adult Grey for season three of the series, which adapts Voyager.

[20] In "Je Suis Prest", young John William Grey, second son of Viscount Melton, encounters Highland warrior Jamie Fraser and his wife Claire in Scotland near where his British regiment is camped.

In the mistaken belief that Claire is an English prisoner of the Highlanders, Grey tries to "save" her; Jamie subdues him but spares his life.

[4][22] Pri Figueiredo of Moviepilot called the change "a wasted opportunity to show viewers that Jamie Fraser is more than a bulky and sensual sex toy for Claire",[4] but Terri Schwartz of IGN wrote that "Lord John William Grey's first appearance did not disappoint, and it did a great job establishing who he is as a character without overplaying his future importance.

"[23] As in Voyager, the season three episode "All Debts Paid" finds an adult Grey as the new governor of Ardsmuir Prison, where Jamie has been incarcerated.

He tells Jamie that Stephen Bonnet, the convicted criminal who raped Brianna, is not dead as they believed, and has been sighted in Wilmington, North Carolina.

Most notably, Grey is also featured in his own Lord John series of historical mystery novels and shorter works that all take place between 1756 and 1761, during the events of Voyager.

[24][25] When Gabaldon was invited to write a short story for the 1998 British anthology Past Poisons: An Ellis Peters Memorial Anthology of Historical Crime, she was interested in the challenge of writing a shorter work but hesitant to use any of the main characters from the Outlander series for fear of creating "a stumbling block in the growth of the next novel.

[25] They can be generally categorized as historical mysteries, and the three novels are shorter and focus on fewer plot threads than the main Outlander books.

"[42] Comfortable with his sexuality but necessarily "discreet", Grey navigates mystery and intrigue "with characteristic élan, intelligence, and fortitude, assisted by jeweled goblets of wine and meaningful glances from fetching men.

[46] He had been taught the use of a blade starting from age three,[47] and when John was seven, his godfather had begun taking him to the Beefsteak Club every Wednesday for lunch.

During the events of Dragonfly in Amber (1992), he comes across Highland warrior Jamie Fraser and his wife Claire in Scotland while exploring the hills surrounding the English campsite.

In the mistaken belief that Claire is an English prisoner of the Scots, Grey tries to "save" her; Jamie breaks his arm but spares his life.

At eighteen, Grey enters into a relationship with George Everett, who takes him to the Lavender House—a discreet club in London that caters to homosexual men.

[50] In 1755, a scandal involving Everett causes Grey—now a major—to be reassigned to Ardsmuir Prison in Scotland, where he serves as Governor for a year and a half.

After Culloden, Jamie had lived in hiding for seven years, but had finally turned himself in to the English so that the starving people at his estate of Lallybroch could collect the reward on his head.

In 1756, after the prison is successfully rebuilt into a fortress, Grey arranges for Jamie to be paroled to Helwater, under the eye of family friend Lord Dunsany, instead of being transported to the American colonies for seven years of indentured servitude.

[51] Grey also meets and is joined in his adventure by the handsome Hanoverian Captain Stephan von Namtzen, Landgrave of Erdberg, and takes young Tom Byrd into his employ as his valet.

In addition to puzzling out the Trevelyan mystery, Grey helps solve the murder of a fellow soldier who had been suspected of espionage.

[30] In Lord John and the Succubus (2003), Grey is in Prussia serving as the English liaison officer to the First Regiment of Hanoverian Foot.

[32] Grey returns to the 46th Regiment, which is assigned to fight under Duke Ferdinand of Brunswick and chases French and Austrian troops around in the Rhine Valley for weeks until the Battle of Krefeld.

[34] In 1760 in The Scottish Prisoner (2011), Grey and Jamie Fraser find themselves traveling together to Ireland to try to bring back an English soldier with the intent of instigating court-martial procedures against him.

In August 2016, Joanna Robinson of Vanity Fair called Grey "a character so popular, Gabaldon eventually spun him off into his own novels".

[53] TooFab.com called Grey a "fan favorite", noting that followers of both the book and TV series are eager for a spin-off featuring the character.