The son of the Rev. Frederick Bond Cowl (1853-1937; e.m. 1877), he was educated at Hertford Grammar School and Cliff College, before beginning his formal ministerial training at Headingley College. A few months after his ordination, when war broke out in Europe, he volunteered to become an Army Chaplain and on Christmas Eve 1914 took up his new position at the Wesleyan Soldiers' Home at Bordon Army Camp in Hampshire. In August 1915 he was attached to the 12th and 13th Durham Light Infantry and began his overseas service with the 68th Division. His time in France was cut short when he was severely wounded during enemy action in Flanders. At first it was uncertain whether he would survive his injuries, but following surgery to remove shrapnel from his neck and jaw he was sent back to Blighty for recovery. Ten days later he was on the ill-fated hospital ship HMHS Anglia, which hit a German mine in the Channel - the first in the war to be sunk by enemy action. There were many casualties, but Herbert had found the strength to help save some of the wounded and it was for these selfless acts of heroism that he became one of the first Wesleyan Army Chaplains to be honoured by the King with the Military Cross for exemplary gallantry.
Herbert had a long and very happy life, serving the Methodist Church until his death in 1971. The story of his experiences as an Army Chaplain, told by his granddaughter, Sarah Reay, was published in 2016, under the title The Half Shilling Curate, which was the way he signed himself when writing to his parents from France and Flanders.