Robert Gilbert Vansittart, 1st Baron Vansittart, was born on June 25, 1881, at Wilton House, Farnham, Surrey, England.

He was a British diplomat and author. He was educated at Eton College, where he was a member of the exclusive Eton Society and Captain of the Oppidans. He spent two years in Europe, improving his proficiency in French and German and studying the political systems. In 1902, he entered the Foreign Office and was appointed to the British Embassy in Paris in 1903. He then served at the embassies in Tehran (1907-1909) and Cairo (1909-1911). During the First World War, he was joint head of the contraband department and then head of the Prisoner of War Department under Lord Newton. He was the first secretary at the Paris Peace Conference (1919–1920) and principal private secretary to Lord Curzon (1920–1924) and successive Prime Ministers Stanley Baldwin (1928–1929) and Ramsay MacDonald (1929–1930). From 1930 to 1938, Vansittart was appointed Permanent Under-Secretary at the Foreign Office, supervising the work of Britain's diplomatic service. Vansittart was appointed a Member of the Royal Victorian Order (1906), a Companion of the Order of St. Michael and St. George (1920), a Companion of the Order of the Bath (1927), a Knight Commander of the Order of the Bath (1929), a Knight Grand Cross of the Order of St. Michael and St. George (1931), and a Knight Grand Cross of the Order of the Bath (1938). He was sworn into the Privy Council in 1940 and raised to the peerage as Baron Vansittart of Denham in the County of Buckingham in 1941. Vansittart wrote novels, verses, and plays, e.g., “Les Pariahs” (1902), "Collected Poems of Robert Vansittart" (1934), “Dead Heat” (1939), and "Black Record: German Past and Present" (1941). His autobiography, “The Mist Procession”, was published posthumously in 1958.

In 1921, he married Gladys May Heppenheimer (1891–1928), and in 1931, he remarried Sarita Enriqueta Ward (1891–1985). He died on February 14, 1957, in Denham Place, Denham, Buckinghamshire, England.