After having a short stint of four years at the Bar, Justice Kapoor joined State Judicial Service in 1970 and during span of 30 years as Member of Delhi Judicial Service and Delhi Higher Judicial Service and before his elevation as Judge of Delhi High Court had held various important positions such as Rent Controller, Matrimonial Judge, Special Judge for Dowry Death Cases and Secretary, Law, Justice and Legislative Affairs of Govt. of NCT of Delhi and Rent Control Tribunal. After his retirement as Judge of Delhi High Court in April 2004.Justice Kapoor is known for high disposal of cases and a large number of his judgments have been reported in various law journals. He is also the author of two books on marriage & contempt of court.
Justice Kapoor joined State Consumer Disputes Redressal Commission Delhi as its President on 14th July, 2004.  Justice Kapoor retired on 09.04.2009. During his tenure Justice Kapoor decided approximately 11000 cases.