As Holmes's friend and confidant, Watson has appeared in various films, television series, video games, comics and radio programmes.

Part one of the first Sherlock Holmes story, A Study in Scarlet, is subtitled Being a reprint from the Reminiscences of John H. Watson, M.D., Late of the Army Medical Department.

)[11] He joined British forces in India with the 5th Northumberland Fusiliers before being attached to the 66th (Berkshire) Regiment of Foot, saw service in the Second Anglo-Afghan War, was wounded at the Battle of Maiwand (July 1880) by a jezail bullet,[a] suffered enteric fever and was sent back to England on the troopship HMS Orontes following his recovery.

He was left with good prospects, but he threw away his chances, lived for some time in poverty with occasional short intervals of prosperity, and finally, taking to drink, he died".

At the end of the first published Holmes story, A Study in Scarlet, Watson is so incensed by Scotland Yard claiming full credit for its solution that he exclaims: "Your merits should be publicly recognised.

The only point in the case which deserved mention was the curious analytical reasoning from effects to causes, by which I succeeded in unravelling it"; whereupon Watson admits, "I was annoyed at this criticism of a work which had been specially designed to please him.

Sometimes Watson (and through him, Doyle) seems determined to stop publishing stories about Holmes: in "The Adventure of the Second Stain", Watson declares that he had intended the previous story ("The Adventure of the Abbey Grange") "to be the last of those exploits of my friend, Mr Sherlock Holmes, which I should ever communicate to the public", but later decided that "this long series of episodes should culminate in the most important international case which he has ever been called upon to handle" ("The Second Stain" being that case).

In "The Adventure of the Blanched Soldier", one of only two stories narrated by Holmes himself, the detective remarks about Watson: "I have often had occasion to point out to him how superficial are his accounts and to accuse him of pandering to popular taste instead of confining himself rigidly to facts and figures", but the narrative style seldom differs, and Holmes confesses that Watson would have been the better choice to write the story, noting when he starts writing that he quickly realizes the importance of presenting the tale in a manner that would interest the reader.

In "The Red-Headed League", for example, Watson introduces Jabez Wilson: "Our visitor bore every mark of being an average commonplace British tradesman, obese, pompous, and slow"—wearing "a not over-clean black frock-coat".

[17] Watson used to be an athlete: it is mentioned in "The Adventure of the Sussex Vampire" (1924) that he used to play rugby union for Blackheath, but he fears his physical condition has declined since that point.

For instance, in "The Adventure of the Dying Detective", Holmes creates a ruse that he is deathly ill to lure a suspect to his presence, which must fool Watson as well during its enactment.

To that effect, in addition to elaborate makeup and starving himself for a few days for the necessary appearance, Holmes firmly claims to Watson that he is highly contagious to the touch, knowing full well that the doctor would immediately deduce his true medical condition upon examination.

For example, in The Hound of the Baskervilles, Watson efficiently clears up several of the many mysteries confronting the pair, including Barrymore's strange candle movements turning out to be signals to his brother-in-law Seldan, and Holmes praises him for his zeal and intelligence.

In "The Adventure of the Solitary Cyclist," Watson's attempts to assist Holmes's investigation prove unsuccessful because of his unimaginative approach, for example, asking a London estate agent who lives in a particular country residence.

Watson comments as narrator: "Familiar as I was with my friend's methods, it was not difficult for me to follow his deductions, and to observe the untidiness of attire, the sheaf of legal papers, the watch-charm, and the breathing which had prompted them."

At the beginning of "The Adventure of the Veiled Lodger," Watson makes strong claims about "the discretion and high sense of professional honour" that govern his work as Holmes's biographer, but discretion and professional honour do not block Watson from expressing himself and quoting Holmes with remarkable candor on the characters of their antagonists and their clients.

The events related in "The Adventure of the Second Stain" are supposedly very sensitive: "If in telling the story I seem to be somewhat vague in certain details, the public will readily understand that there is an excellent reason for my reticence.

It was, then, in a year, and even in a decade, that shall be nameless, that upon one Tuesday morning in autumn we found two visitors of European fame within the walls of our humble room in Baker Street."

In the film, Holmes (Michael Caine) is an invention of Watson (Ben Kingsley) played by an alcoholic actor; when Watson initially offered suggestions on how to solve a case to some visiting policemen, he was at the time applying for a post in an exclusive but private medical practice and so invented the fictional Holmes to avoid attracting attention to himself.

Watson appears on the 2010 direct-to-DVD Asylum film Sir Arthur Conan Doyle's Sherlock Holmes, a science fiction reinvention in which he was portrayed by actor Gareth David-Lloyd.

Reflecting on his career as a detective, Holmes (Ian McKellen) comments that Watson took considerable latitude in writing up the cases for publication, to the point that he views the finished products as little more than "penny dreadfuls".

Holmes remarks that several key details of his literary counterpart, including his pipe, deerstalker hat, and 221B Baker Street address, were entirely fictitious.

The 2015 mashup anime film The Empire of Corpses features a younger, re-imagined Watson as the protagonist, in a steampunk world where the dead are reanimated and used as a labor force.

[33] The film is inspired by The Enola Holmes Mysteries, a young adult fiction series of detective novels by American author Nancy Springer.

In the 2004-2012 medical drama House, the character of James Wilson, portrayed by Robert Sean Leonard, is partially based on John Watson.

In the 2010 BBC television show Sherlock, Martin Freeman portrays Watson as a discharged military doctor who strikes a complicated yet good friendship with the brilliant but eccentric Holmes (Benedict Cumberbatch).

The 2012 CBS show Elementary, set in New York City, changes the character to an Asian American woman, Dr. Joan Watson (Lucy Liu), an ex-surgeon turned sober companion.

Watson was also portrayed by English-born actor Michael Williams for the BBC Radio adaptation of the complete run of the Holmes canon from November 1989 to July 1998.

Four series were produced, all written by Bert Coules who had been the head writer on the complete canon project, with Andrew Sachs starring opposite Merrison.

In 1998, Imagination Theatre received the rights from the estate of Dame Jean Conan Doyle to produce new radio stories of Holmes and Watson.