The son of Thomas and Margaret Elizabeth Blanco White, he was educated at St Paul's School, London and Trinity College, Cambridge, from where he graduated second wrangler behind Arthur Eddington in 1904, and was awarded Smith's Prize in 1906. He was called to the bar at Lincoln's Inn in 1907.
On 7 May 1909 he married Amber Reeves, feminist writer, scholar and campaigner. She was the daughter of William Pember Reeves and his wife Maud Pember Reeves. She bore a daughter Anna-Jane in December that year whose biological father was the author H.G. Wells (though Blanco White was Anna's legal father). The Blanco-Whites later had daughter Margaret Justin Blanco White (1911–2001), who became an architect, and a son Thomas Blanco White (1915–2006), a patent lawyer. Through Margaret he was the grandfather of anthropologist Caroline Humphrey and mathematician Dusa McDuff.
- G. R. Blanco White, Q.C. The Guardian (1959–2003) [London (UK)] 30 Mar 1966: 2.
- "Mr. G. R. Blanco White." Times [London, England] 29 Mar. 1966: 12. The Times Digital Archive. Web. 13 Jan. 2015.
- ‘WHITE, George Rivers Blanco’, Who Was Who, A & C Black, an imprint of Bloomsbury Publishing plc, 1920–2015; online edn, Oxford University Press, 2014 ; online edn, April 2014 accessed 13 Jan 2015
- Council Of Legal Education. The Times (London, England), Saturday, Jan 12, 1907; pg. 11; Issue 38228. (1649 words)
- "News in Brief." Times [London, England] 11 Feb. 1936: 14. The Times Digital Archive. Web. 13 Jan. 2015.
- The Times (London, England), Friday, Mar 08, 1940; pg. 5; Issue 48559. (417 words)