Hardcastle was inspired to create the song after watching Vietnam Requiem,[3] 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."[5]
The title "19" comes from the documentary's narrative that the average age of an American combat soldier in the war was 19, as compared to World War II's 26.[6] This claim has since been disputed.[7] 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].[8] 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.[6]
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.[5][6] 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".[5] 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.[5] News interest in the song helped, with the tenth 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 most of the world. Hardcastle produced different mixes of the song to help maintain interest in it.[5] 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".[5] 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 he "had tons of letters from Vietnam vets thanking me for doing something for them".[5]
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."[5]
In 2015, Hardcastle released a charity version of the song for the Talking2Minds organisation, who raise money for troops suffering from Post Traumatic Stress Disorder. This PTSD remix was also found on 19: The 30th Anniversary Collection, a compilation album which included 14 versions of the song such as the Cryogenic Freeze Remix and a version which included samples of Marvin Gaye.[9][10][11]