Clarence Ambrose was born in Woolich (probably misprint of Woolwich) NSW, but was living with his mother, Mrs. Nellie Ferrier Ambrose,  at Simpson St, East Melbourne when he enlisted on 20/1/1916. According to his enlistment record, he was eighteen years old and had done 4 years of Senior Cadets, though he was probably only seventeen. He listed his employment as 'Salesman', was 5' 7" tall and had blond hair and blue eyes.

Clarence Ambrose was taken on strength by the 60th Battalion 1st Rifles. The 60th Battalion had taken a key role in the battle of Fromelles in July, 1916, where it was almost wiped out, suffering 757 casualties in the battle. As a result, it saw little action towards the end of  1916. in early 1917, the Battalion took part in the major advance against the Germans on the Western Front, pushing them back to the Hindenburg line. The gains made in this action were then defended at the battle of Bullecourt, but the 60th's next major action was at Polygon Wood on 26th September, 1916. Clarence Ambrose was sent to France and taken on strength on 6/11/1916,  but was transferred in October 1917, listed as 'underage personnel', to the Australian Corps Working Party, having been identified as 'immature' and 'underage'. He had had several bouts of sickness and hospitalisation in early 1917 and this continued in late 1917 and early 1918. He was later given an early return to Australia on 2/1/1919, 'reason not stated' written on his records. 

In the Australian Eectoral rolls of 1924, Clarence Ambrose is recorded as living at 10 Simpson St., East Melbourne with his mother. In 1925, he was in a relationship with Pearl Clapham, by whom he had a daughter, Joan Ambrose. By 1930, he is in Drummoyne, NSW, working as a motor driver. In 1943, he lived at 51 Grey  St., St Kilda, Victoria, describing himself as a traveller. In 1945, he married Bertha May Anderson and in 1949, they are living at 7 Princes St, East St Kilda. In 1963, they were still living together, this time at 3/54 Wellington St, St Kilda. Clarence Ambrose died, aged 67, at Heidelberg in 1966. Bertha was still living in St Kilda in 1980.