He represented India at the 2018 Asian Games where he won the gold in the 800 metres event at Jakarta.

[2] Manjit was born in Ujhana village, Jind district, Haryana, to Randhir Chahal and Bimala Devi.

[5] In 2013 Manjit took part in his first international event, in the 2013 Asian Athletics Championships, at Pune, where he finished 4th place in the Men's 800 metres final clocking 1:49.70 mins.

[7] On March 7, 2018, in the Patiala Federation Cup, he competed in both 800 m and 1500 m and bettered his timings of 1500 m to 3:42.24 and qualified for 1500 m in the 2018 Asian Games.

On 27 August 2018, Manjit Singh, stunned everyone and compatriot Jinson Johnson to win gold in the Men's 800 metres at the Asian Games after 36 years for India where he clocked 1:46.15 as his personal best.