Born in 1730 he was his parents' fourteenth and youngest child. In 1740 his father died and his eighteen-years-older brother became King Friedrich II. Of the four brothers Ferdinand was of the least consequence. On 27 September 1755 Ferdinand married his niece, Luise of Brandenburg-Schwedt, and seven children were born. When Friedrich II was ill at Breslau in 1757, Ferdinand went to keep him company there.
In 1777 the Elector of Bavaria died and the Empress Maria Theresa decided to annex his territories, expecting Friedrich II to be too ill to prevent her. However, Friedrich II asked him to command an army but Ferdinand point-blank refused. Friedrich II sent him a sarcastic letter urging him to take great care of his health and saying it was quite right to sacrifice his adored and favourite profession to it.The command went to the retired Prince Heinrich.
In 1786 Mirabeau visited Prussia but this was not a success and, in his 'Histoire secrete de la Cour de Berlin', which was full of spiteful gossip, claimed Ferdinand not to be the father of his children.

Friedrich II died in 1786 and was succeeded by a nephew, Friedrich Wilhelm II who died in 1797. When Ferdinand died, on 2 May 1813, Prussia's ruler was his great-nephew King Friedrich Wilhelm III.
 

Source: Leo van de Pas