He joined Gagrat & Co., a law firm, as a clerk and later went on to work with Feroze Damania who was a highly respected "firebrand" labour lawyer.

[10] On 3 March 2011, a three-member bench headed by Kapadia, quashed the appointment of Chief Vigilance Commissioner, Polayil Joseph Thomas, made by the High Power Committee comprising Prime Minister Manmohan Singh, Home Minister P. Chidambaram and Leader of the Opposition Sushma Swaraj (dissenting).

The judgment caused severe embarrassment for the government and made Manmohan Singh admit the error in appointment.

Former IAS officer, S. M. Murshed writes, 'the ratio decidendi of the Hon’ble Supreme Court is a bit difficult to comprehend, for, in the last analysis, the entire case against Thomas rested on a solitary, misconceived FIR which was filed as an afterthought and which should never have been filed.

'[12] Kapadia was part of the three-member Supreme Court bench that decided a PIL filed by two NDA leaders seeking the cancellation of bail of Rashtriya Janata Dal chief Lalu Prasad and his wife and former Bihar Chief Minister Rabri Devi for their interference in the judicial process in the disproportionate assets (DA) and Income Tax cases against them.

[15] Kapadia delivered a landmark judgement relating to succession of property in 30 April 2005 in which he ruled out the possibility of conducting the DNA test.