Charles grew up in Highworth, near Swindon, with his parents John and Annie Kirby and his older brother, also named John. Charles and John Jr emigrated to a town called Dorrigo in New South Wales, about half way between Brisbane and Sydney. They set up a farm, which they named Swindon Farm, and the pair worked there until they joined the war effort.
Charles enlisted in Rutherford on the 17th of September 1915, by which point John Jr had already been killed in action in Gallipoli. Charles joined the newly-created 33rd Battalion. He sailed from Sydney to the United Kingdom in May 1916. Arriving there in early July, he spent the next four months training. He managed to secure a short period of leave while he was training, and returned to Swindon to visit his parents.
Charles crossed to France in late November, and moved into the trenches of the Western Front for the first time on 27 November, just in time for the onset of the terrible winter of 1916-17. A little over two months after arriving, on the 8th of February, Charles' unit were engaged in bombarding the opposing German trenches. The Germans retaliated with their own bombs, one of which badly injured one of Charles' men. Charles immediately rushed to the wounded soldier's assistance, and rendered first aid under heavy shell fire. Hearing a bomb coming towards him, he leant over the wounded man to save him from further injury and took the whole of the explosion himself. His leg had to be amputated above the knee, and he was rushed to hospital in Boulogne, where he died ten days later. He was buried in Boulogne Eastern Cemetery alongside over 5000 other commonwealth soldiers who died in Boulogne's hospitals during the war. He left behind a wife, Ileene, and a one-year-old named Charles, who died aged 14 in a shooting accident.
Lieutenant-Colonel L J Morshead wrote to John Sr immediately after Charles was wounded, telling him that "throughout your son displayed great courage and coolness. I know that you will be very proud of him. You have reason to be so!". Charles was recommended for the Military Cross for his bravery and selflessness that day, but it was never awarded.