Percy Victor Clark was the eldest son of Charlotte and Samuel Clark and brother to Leslie Henry Charles Clark. Like his borther he was born in Balmain Street, Richmond, and went to school at Brighton St. State School, Richmond. He served in the Senior Cadets and had continued his training after leaving school. He was living at home with his parents at 132 Powlett St., and working as an Electrical Wireman prior to enlisting on 17 April, 1916, a week afer his younger brother. 

He trained at Broadmeadows, where he was placed in the 3rd Divisional Supply Company as a Driver Motor Transport, embarking on HMAT Persic A34 from Melbourne for England on 3 June, 1916. From the ship, he was sent to Australian Army Service Corps Training Depot at Bhurtpore on 7 July, 1916, and from there to Chelsea, where he served as a driver with the Australian Army Supply Column Motor Transport until 16 December, 1917. At this point, he was moved to duty at the General Hospital, Codford. he remained therefor six months until mid-1918, when he was moved to Bhurtpore Barracks on 6 July, 1917, then a day later Parkhouse, again with the Australian Army Service Corps Motor Transport Detail. 

From Parkhouse, Percy Clark was sent to France on 30 August, 1918, marching in to the Australian General Base Depot on 1 October and taken on strength with the 2nd Army Motor Transport Company on 2 October. Two days later, he marched out ot Rouelles, where he remained until 12 April the following year, 1919, when he was given leave in England. He rejoined from leave on 3 May, 1919,and continued to serve until June.

On 5 June, 1919, Clark left France for England to be demobbed, landing at Southampton on 6 June.He embarked for home on board SS Norman on 4 July, disembarking in Melbourne on 18 August. He was discharged form the army on 2 October, 1919.

From this point, there is little information about him. In 1919, he was back living with his parents in Powlett Street, East Melbourne, but otherwise, he cannot be found on the Electoral Rolls. On 26 September, he was still at Powlett Street, and sent in an application for a War Service Home grant. THercis nothing in further Electoral Rolls or in the Birth, Marriage and Death Index.