At the Olympic event, he made his way to the second round in the Bantamweight 54 kg category beating Frenchman Ali Hallab on points 12-5. In the round of 16, he beat World Champion Sergey Vodopyanov, coming from 2-6 down in the second round of the bout. The score was tied 9-9 at the end of the fourth round but the judges decided in Kumar's favor because he landed a greater number of punches. He lost 3-10 to Veaceslav Gojan of Moldova in the quarter finals on 18 August 2008. He was coached by the Indian boxing coach Gurbaksh Singh Sandhu.