This incarnation's main companions included Amy Pond (Karen Gillan), her husband Rory Williams (Arthur Darvill) and the mysterious Clara Oswald (Jenna-Louise Coleman).

He also frequently appeared alongside River Song (Alex Kingston), a fellow time traveller with whom he shared a romantic storyline, and he was the last Doctor to appear alongside the long-serving companion Sarah Jane Smith (Elisabeth Sladen) prior to the actress' death, featuring in two episodes of the spin-off programme The Sarah Jane Adventures.

David Tennant announced at the National Television Awards on 29 October 2008 that he would be quitting the show, in 2010, because he felt that the four years he spent portraying the Doctor was enough.

The Doctor's initial outfit, chosen within the narrative of "The Eleventh Hour" from an array of clothes found in a hospital, is a brown tweed jacket with elbow patches, bow tie, braces, blue trousers and black, ankle-high boots.

In later stories, a green moleskin overcoat makes its way into the Doctor's ensemble, occasionally replacing the Harris jacket.

The original tweed jacket is lost in the episode "Flesh and Stone" but replaced in "The Vampires of Venice", then becomes a plot point for the story arc for the season.

After appearing in Victorian period clothing throughout "The Snowmen", the Doctor's costume changes to generally more somber colors beginning in "The Bells of Saint John" where he exchanges the monk's robes for an eggplant purple cashmere frock coat and a variety of waistcoats, and bow tie.

This began a running gag with "cool" headgear, including a beige Stetson, a black top hat, and the recurring fez, most of which were destroyed by River Song.

The original look had a swashbuckling feel which Doctor Who Magazine editor Tom Spilsbury described as "a little like something Captain Jack Sparrow wears in the Pirates of the Caribbean movies".

Smith debuts fully in "The Eleventh Hour", where he first meets Amy Pond (Karen Gillan) as a child while investigating a mysterious crack in her wall.

Many years later, Amy joins the Doctor as his travelling companion on the eve of her marriage to Rory Williams (Arthur Darvill).

The Doctor also confronts his dark side in "Amy's Choice", where he is put through trials by a manifestation of his self-loathing, the Dream Lord (Toby Jones).

In the final episodes "The Pandorica Opens" and "The Big Bang", an unknown force makes the TARDIS explode, causing the universe to collapse in on itself.

River assists Amy in remembering the Doctor back into existence; he returns at her wedding to Rory, and the couple rejoin him as his companions.

Eventually, Amy unknowingly lets slip that the Doctor dies in "The Almost People", when it also turns out that she is pregnant and has been kidnapped by the nefarious Madame Kovarian (Frances Barber).

The Doctor also learns that Melody—though Rory and Amy's child—is part Time Lord due to being conceived in the TARDIS, and she will grow up to become River Song.

In "Let's Kill Hitler", the Doctor encounters a younger iteration of River and learns she has been conditioned by the Silence, explained to be a religious order, to assassinate him.

In "The Wedding of River Song", he devises an escape by concealing himself within the Teselecta, which is disguised to look like him, to make it seem he is shot and burned as history records.

The Doctor subsequently "retires" to a secluded lifestyle in Victorian London, until the 2012 Christmas special "The Snowmen," when he is inspired to save the world by a barmaid/governess called Clara (Coleman) who he considers an ideal companion.

The Doctor succeeds in "The Bells of Saint John", saving a present-day version of Clara Oswald from agents of the Great Intelligence.

Led by the Moment into the midst of the Time War, the Doctors realize they have the potential to change its outcome and enlist the aid of their previous incarnations in an uncertain bid to save Gallifrey from destruction.

As an effect of time travel, only the Eleventh Doctor will remember saving Gallifrey; he learns from a cryptic curator (played by Tom Baker) that his plan worked.

During this time, a faction of the Church led by the Silence breaks away and attempts to avert these events by destroying the Doctor earlier in his timeline, as seen in series 5 and 6.

He hallucinates a final farewell to Amy Pond and delivers a eulogy to his present incarnation, before abruptly completing his transition into the Twelfth Doctor (Peter Capaldi).

He also appeared alongside the Tenth Doctor in The Jago and Litefoot Revival in 2017, narrated by Trevor Baxter and Christopher Benjamin.

The third episode is the video game TARDIS, and the fourth is The Shadows of the Vashta Nerada, featuring the titular enemy return in an underwater setting.

[33] In The Guardian, Daniel Martin concurred, stating that "Smith inhabits the role from the moment he pops up...[he] carries off the youthful vigour of a new body and the ancient professorial wisdom with easy panache".