"19" features sampled narration (voiced by Peter Thomas), out-of-context interview dialogue ("I wasn't really sure what was going on") and news reports from Vietnam Requiem the ABC television documentary about the post-traumatic stress disorder suffered by Vietnam veterans. In 2009, the song placed at 73 on VH1's 100 Greatest One-Hit Wonders of the 80s.
Hardcastle was inspired to create the song after watching Vietnam Requiem, and comparing his own life at 19 to those of the soldiers featured: "...what struck me was how young the soldiers were: the documentary said their average age was 19. I was out having fun in pubs and clubs when I was 19, not being shoved into jungles and shot at".
The title "19" comes from the documentary's claim that the average age of an American combat soldier in the war was 19, as compared to World War II's 26. This claim has since been disputed. Undisputed statistics do not exist, although Southeast Asia Combat Area Casualties Current File (CACCF), the source for the Vietnam Veterans Memorial, shows a large number of deaths (38%) were ages 19 or 20. According to the same source, 23 is the average age at time of death (or time of declaration of death). The song also comments that while the tour of duty was longer during World War II, soldiers in Vietnam were subjected to hostile fire [more frequently] almost every day.
Musically, the song was inspired by electro, particularly Afrika Bambaataa, although Hardcastle also "added a bit of jazz and a nice melody", and beyond the sampling of the documentary narration, the song incorporated pieces of interviews with soldiers. The song's pivotal hook: the repetitive ""N-n-n-n-nineteen", was chosen due to the limitations of the early sampling technology used. The E-mu Emulator could only sample for two seconds, so the hook was based around "the only bit of the narrative that made sense in two seconds". Hardcastle wasn't optimistic about the song's chances in the charts. His previous two singles for independent labels had failed to make it into the UK's Top 40 and the musical policy at Radio 1 was felt to be unsupportive of dance music. News interest in the song helped, with the 10th Anniversary of the End of the Vietnam War seeing Hardcastle interviewed by Alastair Stewart of ITN.
Tony Blackburn, then breakfast DJ for Radio London was an early supporter of the song and it quickly reached number 1 in the UK and around the world. Hardcastle produced different mixes of the song to help maintain interest in it. Although the song did not climb as high in the United States chart, Hardcastle claims "it outsold everybody else for three weeks solid, it only reached number 15, because back then the chart was based on airplay as well as sales". The song was held back in the US by some radio stations refusing to play it, feeling that the song took an anti-American stance, something Hardcastle denies, noting "I had tons of letters from Vietnam vets thanking me for doing something for them".
The song's reliance on sampling also caused problems with legal clearance. Ken Grunbaum recalled in 2012 that "there were no precedents for something like this. We ended up having to pay royalties to the narrator, Peter Thomas".
After the song's unexpected, rapid climb to the top of the UK Singles Chart, Chrysalis asked directors Jonas McCord and Bill Couterie to rush a video into production. Due to the lack of a band able to perform the song, the video was primarily composed of clips from the Vietnam Requiem documentary, edited together by Ken Grunbaum. The first version of the video included footage from the television networks NBC and ABC, including a newscast by ABC anchorman Frank Reynolds. After it was aired on MTV in the US, NBC and ABC objected to the "bad taste" of using the serious clips in a "trivial" form of "propaganda". McCord and Couterie were forced to produce a new cut incorporating public domain footage, but ABC permitted Reynolds' audio to remain. Couterie asserted at the time that the television networks opposed the video because it involved rock music:
What is the difference between the words in our song and the 7 o'clock news? The only difference is rock'n'roll. And why did they love the documentary and hate the video so much? Every word in the song is from the film, and there was never any argument with the facts. The only difference is the music.
^Roush, Gary (2 June 2008). "Statistics about the Vietnam War". Vietnam Helicopter Flight Crew Network. Archived from the original on 7 December 2009. Retrieved 6 December 2009. Assuming KIAs accurately represented age groups serving in Vietnam, the average age of an infantryman (MOS 11B) serving in Vietnam to be 19 years old is a myth, it was actually 22. None of the enlisted grades have an average age of less than 20.