The regiment in its current composition was formed in 1948 when the Citizens Military Force (CMF) was re-raised after the completion of the demoblisation process following the end of the Second World War and it was formed through the amalgamation of three previously existing regiments.
Through these predecessor units, 4/19 PWLH can trace its lineage back to the 19th Century and today it is the custodian of the battle honours earned by these units.
During the period 1960–65 the regiment had a Regular squadron attached to it, although in 1965 this squadron was removed from the order of battle and its personnel used to form a number of other Regular cavalry units that continue to exist in the Australian Army today.
These units subsequently served during the Vietnam War and many of their personnel continued to wear regimental accoutrements while in South Vietnam.
Today 4/19 PWLH is a Reserve regiment and forms part of the 4th Brigade, 2nd Division based in Victoria.
Recently it was re-roled from an armoured personnel carrier unit operating M113s, to a light cavalry unit operating modified Landrover four-wheel drives. This was in line with the Army wide restructure of the Reserve units of the Royal Australian Armoured Corps (RAAC).
The motto of 4th/19th Prince of Wales's Light Horse is ‘Ich Dien’, which is German for ‘I Serve’. This is also the motto on the Heraldic Badge of His Royal Highness, the Prince of Wales.