Sangwan was born on 1 January 1993 in Shekhpura village of Haryana state's Karnal district to a Jat family.[4][5] He started his career at avery early age, picking up the gloves when he was only 11, at his uncle’s boxing academy in the village. He soon showed his mettle and went from the state levels to the national levels when he was only 16. After shining through the national levels by winning two gold medals, he came to the spotlight when he won the Gold at the Asian Olympic Qualifiers in Astana, Kazakhstan in April 2012. He kept the faith of the national selectors when he qualified for the London Olympics after he was picked for the Olympic qualifiers over 2010 Asian Games silver medalist and Olympian Dinesh Kumar.
Sumit Sangwan represented India in the AIBA World Boxing Championships in Almaty Kazakhstan.[6] He lost out to Adilbek Niyazymbetov of Kazakhstan in the quarterfinals of the World Boxing Championships.[7][8][9]
Sumit participated in the World Series of Boxing for American outfit USA Knockouts in 2014.