The regiment was one of four 'large' regiments formed after the 1966 Defence White Paper through the amalgamation of units of the Light Infantry Brigade.

The regiment was formed on 10 July 1968 as a large regiment by the amalgamation of the four remaining light infantry regiments of the Light Infantry Brigade:[1] On 31 March 1969 the 4th Battalion The Light Infantry (formerly The Durham Light Infantry) was disbanded leaving three regular battalions.

[1] The regiment was active all through The Troubles in Northern Ireland with eight soldiers from the regiment killed in the Ballygawley bus bombing.

[1] In December 2004, it was announced that, as part of the planned Army restructuring published in Delivering Security in a Changing World, the Light Infantry would gain a new battalion through amalgamating with the Devonshire and Dorset Regiment and the Gloucestershire elements of the Royal Gloucestershire, Berkshire and Wiltshire Regiment.

[8] However, on 24 November 2005 it was further announced by the Ministry of Defence that, after discussions between the Light Infantry, the Devonshire and Dorset Regiment, the Royal Gloucestershire, Berkshire and Wiltshire Regiment and the Royal Green Jackets, the four regiments would amalgamate to form a single, large regiment to be named The Rifles.