Harry Watt was born in 1906 in Edinburgh, Scotland. He studied at Edinburgh University, but failed to complete his degree. In 1932 he joined John Grierson at the Empire Marketing Board Film Unit. Watt gained first valuable experience assisting John Taylor on Robert Flaherty's film Man of Aran (1934). In 1936, on Grierson's recommendation, he became a director for the newly-established London unit of the American newsreel series March of Time. For the GPO Film Unit, Watt went on to direct most of Night Mail, best-remembered of all the 1930s documentaries.
He continued his film work during wartime in Crown Film Unit, his surely most remembered film from that time is Target for To-night (1941) was the first British documentary to reach a wide audience in commercial cinemas. He later joined Alberto Cavalcanti in Ealing studios. After the war he made two African sagas Where No Vultures Fly(1951) and West of Zanzibar (1954). The films were very popular and became two of Ealing's biggest box-office successes. His last cinema films, two minor ventures made in Norway and Denmark, emerged in 1961. Harry Watt died in 1987 in Amersham, UK.