Percy Twentyman-Jones was born in Beaufort, South Africa in 1876.
Twentyman-Jones played on the wing at rugby for Western Province and, in 1896, was picked to play for South Africa in the Test series against the touring British Isles team. Twentyman-Jones played in the first Test, which the British Isles won 8-0, missed the second Test, but played in the third and fourth Tests. Twentyman-Jones scored his one and only international try in the third Test which South Africa lost 3-9; the fourth Test, which South Africa won 5-0, was South Africa's first Test victory.
Twentyman-Jones also played cricket for Western Province and, after scoring 33 and 50 - the 50 being out of a second innings total of 80 - against the touring Australian team in 1902, was selected to play for South Africa against Australia in the third Test; Twentyman-Jones was not able to repeat the form he had shown when playing for Western Province and, after scoring ducks in both innings of the Test, was not picked again. In total, Twentyman-Jones played only 10 games of first-class cricket, in which he scored 306 runs at an average of 18 and with a top score of 53.
Twentyman-Jones qualified as a lawyer in 1898 and subsequently became a judge. He died in 1954 at the age of 77.