A native of Newbridge, County Kildare in Ireland, born on 26 November 1873, McCristell enlisted at an early age into the Royal Inniskilling Fusiliers.

By 1909 he had attained the rank of Staff Sergeant Major in the 5th Battalion of the Wellington Rifle Volunteers and providing instruction from Featherston in the south to Woodville in the North.

[3] In March 1911 McCristell was appointed as a Sergeant Major in the Permanent Forces in the position of Area Non Commissioned Officer in the Wairarapa region.

In April 1916 McCristell was appointed as Major James O'Sullivan's successor as Director of Equipment and Ordnance Stores.

McCristell married Ellen Spence on 6 February 1910 at Woodville, New Zealand, and had three children; Thomas (8 Apr 1912), Mary (17 Oct 1913) and Nancy (27 Aug 1916).