William Hartnell was rather like his character off screen, and could regularly be heard barking at actors who fluffed their lines. Indeed, a visiting brigadier was highly complementary to Hartnell's drilling technique.
The first film in the "Carry on..." series. A further thirty were produced until 1992.
In this first in the "Carry on..." series, Kenneth Williams, Charles Hawtrey, Hattie Jacques, Kenneth Connor and Terry Scott would go on to be regulars in the series.
"Carry on, Sergeant" is a normal expression for an Army officer to use; the American equivalent is, "As you were." The title was used to cash in on the popularity of The Ship Was Loaded (1957), which was written by Val Guest. At the time, the success of the film prompted applause and audience laughter in serious settings where the phrase was used, including amongst audiences of the film The Devil's Disciple (1959).
The film had not been conceived as the start of a movie series. Only after the film's surprising success did the producer Peter Rogers and the director Gerald Thomas set about planning a further project. After reusing the "Carry on..." prefix and some cast members in their next project Carry on Nurse (1959) and having success with that film, the "Carry on..." series of films evolved.