34-year-old Kumar had defeated four-time MLA from Sultanpur Majra, Jai Kishen, by 64,439 votes getting the giant-killer tag. He had the highest margin of victory in terms of percentage.
In the 2013 elections, contesting from the same constituency, he had lost by 1,112 votes.
He did his LLB from the Charan Singh University, Meerut, and graduation from Delhi University in 2004.
Kumar came in touch with Kejriwal for the first time during the India Against Corruption campaign in 2012. He is known to contest cases of the poor and socially backward persons free of cost.
He has been given the charge of SC/ST Welfare and Women and Child Welfare.