Rupert Erroll Victor Buxton was born on May 10, 1900, to Sir Thomas Fowell Victor Buxton and Anne Louisa Matilda O'Rorke. He was their seventh and youngest son.
As a child, he attended Summer Fields prep school in Oxford. He enjoyed writing poetry (which he was very talented at), as well as playing the piano and organ. At fourteen, he won a scholarship to Harrow School in London, where he was appointed Head Boy. He was an exceptionally kind young man and found interest in supporting causes like the London Association for the Blind. After he left Harrow School, he studied at Cambridge University and Christ Church, Oxford. There he befriended Michael Llewelyn Davies, one of J.M. Barrie's young friends. Both boys were interested in poetry and theater, and their friendship blossomed quickly. Rupert and Michael became nearly inseparable.
On May 19, 1921, nine days after Rupert's twenty-first birthday, he and Michael were at Sandford Lock when they decided to go swimming in Sandford Pool, an infamous location for accidental drownings. The coroner concluded that Michael, a weak swimmer, drowned accidentally and Rupert drowned trying to save him. Their bodies were found with their hands clasped together. Both men suffered from depression, however, and some speculate that they died in a suicide pact.
Rupert was survived by his mother; brothers Thomas, Roden, and Clarence; and sister, Lucy. He was preceded in death by his brothers Jocelyn (1916) and Maurice (1919), as well as his father (1919). He was buried at St. Thomas Churchyard in Upshire.