[2] He was born in Ernstbrunn, Austria, the son of Prince Heinrich XXXIX Reuss and Countess Antonia of Castell-Castell.

Heinrich IV became head of the princely family after the previous Prince Heinrich XLV went missing in 1945 and was declared dead in 1962.

He lived with his family at Castle Ernstbrunn in Lower Austria.

His son, Heinrich, also bought a piece of expropriated property in Eastern Germany.

On 10 June 1954 the prince married Princess Marie Luise of Salm-Horstmar (1918-2015), daughter of Otto, Prince of Salm-Horstmar and Countess Rosa of Solms-Baruth.