Rajesh Kumar was born on 1 January 1980 in Munger, Bihar, and came from the Lal Darwaza area of the district. He joined the Border Security Force on 12 November 2007 and was posted to the 84th Battalion, his parent unit in the BSF. Over the course of his service, he developed considerable operational experience and took part in security duties in areas affected by armed insurgency.
In September 2018, Rajesh Kumar was deputed to the Jharkhand Jaguar, the state's specialised force for counter-insurgency operations. He became associated with its assault operations and was entrusted with leading an assault group. During his tenure with the force, he participated in several operations against armed extremist groups operating in the forested areas of Jharkhand.
On 28 September 2021, security forces launched a search operation in the Latehar area after receiving information about the presence of JJMP extremists. Rajesh Kumar was leading the assault team when the security personnel encountered the armed group in the forest. A gun battle followed, during which he suffered serious bullet injuries.
Rajesh Kumar was evacuated from the encounter site and taken to Ranchi for treatment, but he succumbed to his injuries later that day. He made the supreme sacrifice while leading his men during the Latehar counter-insurgency operation. His service was subsequently remembered by the Jharkhand authorities and his fellow security personnel for his leadership and commitment to duty.