Branston was born at Newark-on-Trent, the second son of George Henry Branston, of The Friary, Newark, Nottinghamshire, a wealthy maltster, and his wife Gwynedd, daughter of Adam Eyton, JP, of Plas Llanerch-y-Mor, Flintshire.
[1][2] Branston attended Charterhouse School in Surrey before going up to Hertford College, Oxford.
[3] An all rounder, he won cricket Blues in 1904, 1905 and 1906, and played for Nottinghamshire during the summer holidays as an amateur.
[3] Branston was one of the leading players on the all-amateur MCC tour of New Zealand in 1906–07: he scored 119, one of only two centuries by the team, against Canterbury, and in all matches took 36 first-class wickets at an average of 18.69.
[8] In 1912, Branston married Ethel May, daughter of J. E. Anderton, MBE, MD, of New Mills, Derbyshire.