During Operation Vijay, Rifleman Sanjay Kumar was the leading Scout of a company of 13 JAK RIF for the capture of area Flat Top on 04 July 1999 in Mushkoh Valley, Jammu & Kashmir.

As the attack progressed, enemy automatic fire from one of the sangars posed stiff opposition, thereby stalling the column. Rifleman Sanjay Kumar, realising the gravity of the situation, displayed indomitable spirit and unadulterated courage when he charged the enemy sangar with utter disregard to personal safety. In the ensuing hand-to-hand combat, he killed three of the intruders, and was himself seriously injured. Despite being injured, he charged on to the second sangar. The enemy was taken totally by surprise and they left behind a Universal Machine Gun (UMG) and started running. Rifleman Sanjay Kumar picked up the UMG and killed the fleeing enemy. Although Rifleman Sanjay Kumar was bleeding profusely from his wounds, he refused to be evacuated. This super-human act of rifleman Sanjay Kumar motivated his comrades, who took no notice of the treacherous terrain and charged on to the enemy, thus wresting the area Flat Top from the hands of the enemy.

Rifleman Sanjay Kumar displayed most conspicuous and extraordinary gallantry, cool courage and devotion to duty of an exceptionally high order in the face of the enemy, and was thus awarded the Param Vir Chakra.