In the final of the individual vault, karmakar finished at the top among eight gymnasts with an average score of 13.566. In both her attempts, the 30-year-old received identical scores of 13.566.
North Koreans Kim Son Hyang (13.466) and Jo Kyong Byol (12.966) bagged the silver and bronze medals, respectively.
Earlier, Karmakar won the bronze medal in same event in Hiroshima in 2015.
She became a household name in the country after finishing fourth in the vault final at the Rio Olympics in 2016. Karmakar also bagged a bronze medal in the Glasgow Commonwealth Games in 2014.
Karmakar returned to action last year after serving 21 months ban following a positive test for a banned substance.
