The episode, written by then-new head writer and executive producer Steven Moffat and directed by Adam Smith, saw a complete change in cast and production crew.

In the episode, the Eleventh Doctor (Matt Smith) crashes the TARDIS into the small English village of Leadworth, where he meets a young Scottish girl named Amelia Pond (Caitlin Blackwood).

The Doctor is forced to leave in order to repair damage to the TARDIS caused during his recent regeneration and crash, but promises Amelia he will return in five minutes.

It is also the starring appearances of Smith as the Doctor, Gillan as his new companion and Arthur Darvill as Amy's boyfriend Rory Williams, who would later become a main cast member.

Searching for Zero, which is able to take the form of any unconscious being that it has telepathically linked to, they run across Amy's boyfriend Rory, who helps spot Zero posing as one of the coma patients in his care.

The Doctor directs Amy and Rory to the hospital, while he gate-crashes an online meeting of experts discussing the Atraxi warning to give them instructions.

Intending to take the repaired TARDIS for a short test run, the Doctor returns to Amy's house two years later.

Though Gillan recommended Blackwood, the young actor first had to undergo rigorous auditions,[18] lacking any formal acting experience.

The title of the episode is a play on words, referring both to the introduction of the eleventh Doctor and to the fact that he was nearly too late, the connotation of the phrase.

Moffat explains that she developed a tough element and had become distrustful and cynical due to him not returning as promised, forcing her to accept that he was an imaginary friend.

[19] Moffat was inspired by a crack in his son's bedroom wall and developed the idea into the main story arc for the fifth series.

Moffat thought it would be funny if they showed him hanging out of the TARDIS and nearly crashing into London, which would start an episode set in a small town in a big way.

Moffat's variant had the newly regenerated Doctor reject a variety of foods, with the exception of fish fingers with custard, offered to him by the young Amy.

[12] In the episode, the Doctor snaps his fingers to open the TARDIS, a trick his previous incarnation learned from River Song in "Silence in the Library"/"Forest of the Dead".

[31] As the stills were taken by members of the crew and not computers the result was not perfect, which Adam Smith thought provided an "organic" feel.

[31] The production crew heavily dressed the area, adding flowers, street signs and souvenirs specific to Leadworth.

[19][32] The Doctor hanging out of the TARDIS was filmed with Smith in front of a greenscreen, while the aerial footage of London was achieved with a helicopter.

[12] In post-production, 30 tracks of sound effects, music composed by Murray Gold specifically for the sequence, and Smith's "grunting and groaning" were added.

[44] The show was broadcast two weeks after airing in Britain, as the BBC required a fortnight to edit down the Doctor Who Confidential: Cut Down.

There was no room for the accompanying Doctor Who Confidential due to the hour-long running time, but ABC holds the rights and has made it available on iView.

[47] Daniel Martin of The Guardian called "The Eleventh Hour" "an absolute triumph" and the fact that "the story wisely doesn't waste too much time with an unstable regeneration".

[48] Radio Times reviewer Patrick Mulkern believed it was "obvious" that Smith's Doctor would be "up there with the greatest" and also praised Gillan, though he was unsure of the rescored theme tune.

He also praised Moffat's script for "[offering] funny lines...directorial flourishes and a host of blink-and-miss star turns".

However, he thought the downside to the episode were the "slightly poor effects" and "somewhat lightweight story", and while he called the new title sequence "absolutely beautiful", he was unsure of the new variation of the theme tune.

[51] Dave Golder of SFX magazine gave "The Eleventh Hour" five out of five stars, thinking that Moffat captured "the way children perceive the Doctor" and praising the debuts of Smith and Gillan.

Club reviewer Keith Phipps gave the episode an A−, explaining that he liked Smith "a lot" but was not sure if the Eleventh Doctor was separate enough from the Tenth yet.

Though she felt the series was in good hands with Smith and Gillan, she derided the Atraxi for being "alarmingly static and ultimately uninteresting" and the story's "little substance".

[54] IGN's Matt Wales rated the episode 8 out of 10, praising it for easily fitting into the show's continuity, especially with Smith's portrayal of the Doctor.

However, he thought the "calamity plot" was the "weakest link in an otherwise superb opening episode" and the "whole bunch of disparate elements ... never [gelled] into a satisfying whole".

[55] New York Times reviewer Mike Hale wrote that the episode worked like "a well-oiled piece of machinery", but it came across as "routine" with "none of the over-the-top exuberance" of Davies' run.