[1] Born in Hörde, Westphalia (today part of Dortmund) the son of a merchant, his family moved to Hildesheim three years later.

Rudolf left school at the age of 16 to take acting lessons, making his debut in 1925 as Shylock in Shakespeare's The Merchant of Venice in Düsseldorf.

Two years later he moved to Berlin, where he together with Werner Finck and Hans Deppe founded the cabaret Die Katakombe.

From 1929 onward, Platte performed in more than 200 film roles, embodying the shy and underestimated, likeable "Little Man".

In 1940 he succeeded Ralph Arthur Roberts as director of the Theater in der Behrenstraße in Berlin (right beside the present-day Komische Oper) until its final closure in 1944.