Slavko Grujić finished high school in Marseille, France, before studying at the Sorbonne University in Paris, where he received his Doctor of Law degree (doctorat en droit) in 1897.

[3] In early October 1908, during the Bosnian Crisis, he was Chargé d'affaires in London, when the Dual Monarchy of Austria-Hungary announced the annexation of Bosnia and Herzegovina.

[5] On the eve of the First World War, Grujić was Secretary-General of the Serbian Ministry of Foreign Affairs, and on 30 June met with the Austro-Hungarian secretary of the Habsburg legation in Belgrade, Wilhelm Ritter von Storck, to discuss the Sarajevo assassinations.

Baron Alexander von Musulin, Austria's special envoy, who had written the first draft of the ultimatum, described it as "the most brilliant specimen of diplomatic skill" that he had ever encountered.

As one of the closest collaborators of Prime Minister Nikola Pašić, at the start of January 1916, Grujić was sent to Brindisi as the "Serbian delegate for refugees".

[9] In 1916 he became the first Serbian Ambassador to Switzerland where together with Mable he actively organised humanitarian help to occupied Serbia with the International Committee of the Red Cross in Geneva.

The allied victories of 1918 in which Serbia, as the whole world knows, played an important military role, resulted in the liberation of the Serbs, Croats, and Slovenes whom Austria had held for a century under her cruel yoke.