Subhash was born (25 March 1943) in Dhulia, Maharashtra and had five siblings. He got his Bachelor of Commerce from Pune University in 1964 and moved to Mumbai. Subhash became a Chartered Accountant from Institute of Chartered Accountants of India in 1967. Subhash first job was with Ernst & Ernst in St Louis, Missouri United States which he left in six months and returned to India. He started working as an accountant in a chemical firm at Mumbai.
Subhash founded his real estate Business Runwal Group in 1978 and purchased a 22 acres plot in central suburb of Mumbai.