Newbold first came to note as a rugby player when he represented Cambridge University and won two sporting Blues, in 1902 and 1903.
He won his first international cap while still a Cambridge player, representing England in the 1904 Home Nations Championship.
After leaving university he joined Blackheath, and became a member of the invitational tourists, The Barbarians in 1903.
After the outbreak of World War I, Newbold joined the Royal Engineers and reached the rank of lieutenant colonel.
On 27 September 1924, he married Daphne Gertrude Persse,[5] who served with the British Red Cross Society in both the First and Second World War.