Son of Diederik Jacob van Tuyll and Jacoba Helena de Vicq. Brother of Belle de Zuylen. According to Boswell, he was, in February 1764, "a naval lieutenant in the service of Holland (although he has been for three years on an English man-of-war)".1
Diederik was affectionately referred to as Ditie by the family.
Always of a fragile health, he died in Naples in 1773 while on his way to the home of his sister, Belle, and brother-in-law in Colombier, after having represented the Netherlands at the wedding of the King of Sardinia.2
Boswell describes meeting Diederik at Heer van Zuylen's on January 30 or February 6, 1764.