Along with other forces of the Pakistani military, the NLI has the primary responsibility of conducting ground operations in the interest of defending the strategically-important territory of Gilgit−Baltistan, a Pakistani-controlled region that constitutes part of Kashmir, which has been disputed between Pakistan and India since 1947.

[1][better source needed] The Northern Light Infantry is best known for the extensive assistance and training it provided to the Afghan mujahideen (with backing from the CIA and ISI) during the Soviet–Afghan War.

Following the 1999 Kargil War with India, where the Northern Light Infantry saw extensive combat, the force was converted into a regular regiment of the Pakistan Army.

In 1967 and 1970, two battalions of the NLI were airlifted and deployed to Karachi, Sindh, for internal security duties such as riot control and aiding civil authorities during an election-related period of violence.

The Muslim company of Captain Hassan Khan's 6 Jammu Kahmir infantry battalion, which was traveling from Bunji to Gilgit, joined the scouts as well.

Here, with primarily Saudi Arabian and American financing, the Northern Light Infantry trained Afghan mujahideen fighters in Gilgit−Baltistan before sending them back to Afghanistan with state-of-the-art armaments to fight the Soviet military.

[1][8] In May 1999, Pakistan began operations to occupy key Indian forward posts along the Line of Control (LoC), sparking the Kargil War.

[1] Massive Indian counterattack coupled with heavy diplomatic pressure from the United States forced Pakistan to begin a withdrawal after months of intense fighting.