Arvind P. Datar was designated as a Senior Advocate, Madras High Court, on July 18, 2000. Mr Datar joined the office of N. Natarajan, Senior Advocate, and Mrs Ramani Natarajan. Between 1981 and 1984, he joined the office of Subbaraya Aiyer, Padmanabhan and Ramamani, practicing Income Tax and Central Excise/Customs cases. He set up independent practice on March 1, 1984 before the Madras High Court, mainly on the original side, appellate side and writs, appearing in matters related to income tax and central excise, customs, OSA etc. Subsequently, he appeared before the Supreme Court of India in matters related to constitutional law, corporate, SEBI and tax laws. He has appeared before the High Courts of Karnataka, Bombay, Delhi, Kerala, Calcutta, Allahabad, Gujarat, Patna and Andhra Pradesh. He has also appeared before the Company Law Board, SEBI Appellate Tribunal, Customs Excise and Service Tax Appellate Tribunal and Income Tax Appellate Tribunal at Chennai, Hyderabad, Bangalore and Mumbai (Bombay).

Currently, Mr. Datar is a Trustee, Palkhivala Foundation; Director, Nani Palkhivala Arbitration Centre; Chairman, Maharashtra Building Trust; and Vice-President, Bar Association of India. Mr Datar has also served as Joint Secretary, Tamil Nadu Mediation and Conciliation Centre.

Mr Datar is a Guest Lecturer at the National Law School University of India, Bangalore; ILS Law College, Pune; and School of Excellence, Chennai. He is part of the Guest Faculty at the National Judicial Academy, Bhopal and the Tamil Nadu State Judicial Academy, Chennai. He was a Guest Lecturer at the Cambridge University in 2003 and at the University of Cape Town, South Africa in 2004. He was part of the Visiting Faculty in Taxation Management at the Bharathidasan Institute of Management, Tiruchirappalli from 1984 to 2004. Between 1980 and 1991, he was a Part-time/Visiting Faculty at the Southern India Regional Council of the Institutes and Chartered Accountants, Cost Accountants and Company Secretaries.

Mr Datar has authored the Guide to Central Excise – Law & Practice (two volumes – 6 editions); Guide to Central Excise Procedure (2 editions); and Datar on Constitution of India (2 editions). He has co-authored The Courtroom Genius with Soli J. Sorabjee. He is the General Editor of Essays & Reminiscences: A Festschrift in Honour of Nani A. Palkhivala (January 2020); Editor-in-Chief of Ramaiya's Guide to Companies Act: 11th to 18th edition; and Chief Editor of Kanga & Palkhivala’s “Law and Practice of Income Tax”: 10th and 11th edition (April 2020 launch). He has written over 200 articles in various professional journals and business newspapers.

Mr Datar has a BSc (Honours) from the University of Bombay (1976); BL from the University of Madras (1980); and ICWA from the Institute of Cost and Works Accountants (1982).