Sky du Mont's family, who are related to the famous publishers DuMont Schauberg, fled the Nazis in the 1930s to South America.

[1] He was born in Argentina as the son of a German and the British Chiquita Neven du Mont (1921–2018).

[5] He appeared in three of the commercially most successful German film comedies of all time: In Otto – Der Film (1985) as an aristrocratic-looking swindler, as the villain "Santa Maria" in the Western comedy Der Schuh des Manitu (2001) and in Traumschiff Surprise – Periode 1 (2003), where he reprised his role as "Santa Maria" and played a second role as "William der Letzte" (William the Last), an English duke in the Middle Ages.

In international cinema, Sky du Mont portrayed the Hungarian businessman Sandor Szavost in Stanley Kubrick's Eyes Wide Shut (1999) and played one of the Nazi killers in The Boys from Brazil (1978).

Du Mont also serves as the German narrator of the children series Thomas & Friends.