James Renwick was born at Winlaton in the autumn of 1879, the elder son of James Renwick, a blacksmith and nail maker, and his wife Rosanna Parker. His brother William Ernest was 6 years his junior.
He worked as a journalist for the Newcastle Weekly Chronicle until in 1900 he went to Hatfield Hall, Durham University, with a Theological scholarship. In the Michaelmas Term 1901 he satisfied the examiners in the first year Theology examinations and was awarded a Licentiate in Theology (L.Th.) in 1902. While a student he participated in Union debates, arguing against an Anglo-Japanese alliance.
Ordination as a deacon took place in the chapel of the Bishop of Durham at Auckland Palace in July 1902. He was ordained priest in 1903.
Renwick first served as curate in Hebburn, from 1902, then Greenside from 1904, Monkwearmouth from 1906, Usworth from 1908, Hartlepool from 1911 and Hunwick from 1912 to 1913. While still a curate he returned to Hatfield with a Theological scholarship and gained a B.A. in 1908. While curate at Usworth he met Annie Weatherburn a teacher from Norham in Northumberland, and they married in Hartlepool in the summer of 1911.
He enlisted as a private with the Royal Army Medical Corps, as did many other ordained men, and went to France on 10 July 1915 with a Field Ambulance unit. These were mobile front line medical units that looked after and evacuated injured men. Privates were orderlies, bearers, cooks and washmen and in the Sanitary section they worked on water supplies, cooking bathing and de-lousing. Officers and men of the R.A.M.C. did not carry arms and ammunition. The 45th and 46th Field Ambulances of the R.A.M.C. were deployed to France on the date that James is reported to have gone, so it is likely that he served with one of them. They were with the 15th Scottish Division and dealt with the consequences of the Battle of Loos and the gas attacks at Hulloch. They served on the Somme at Pozieres and Flers Courcelette.
Renwick was promoted to second lieutenant on 20 August 1917 and transferred from the Reserve Battalion of the Royal Irish Rifles to the 10th Battalion a few days later. They took part in the 3rd Battle of Ypres (or Battle of Passchendaele). He must have had further promotion because lieutenant is the rank on his grave stone and memorials.
On 21 March 1918 Lieutenant James Renwick died of wounds in Belfast Military Hospital. It is not yet known exactly when or where he received these wounds. He is buried in Norham Churchyard near his wife: two gravestones bear his name. He is also remembered in the Durham University Roll of Service (1920) and on a plaque in Hatfield College Chapel, there described as a Chaplain to the Forces but this appears to be an error.