Kumar beat Louis Richard Bruno Julie of Mauritius 20:12 in the final bout.
Harpreet Singh and Vijender though had to be content with a silver medals in their respective categories.
Harpreet went down 10:25 in the 91 kg final to local favourite Bradley Michael Pitt at the Melbourne Exhibition Centre while Vijender lost the Welterweight 69 kg 33:26 to Bongani Mwelase of South Africa.