He is the former legal correspondent for the New Statesman;[4] writes about law and policy for the Financial Times;[5] and has previously blogged using the pseudonym Jack of Kent.

[15] After being awarded the Sir Thomas More and Hardwicke Scholarships by Lincoln's Inn,[12] Green was called to the Bar in 1999[12] and became a solicitor in 2001.

[12] Formerly a lawyer at Baker McKenzie, Herbert Smith, and the Treasury Solicitor, he is now (and since 2009) head of the media practice at Preiskel & Co.[3] He was involved on a pro bono basis with Simon Singh's successful libel defence campaign against the British Chiropractic Association.

[3] In 2010, he advised Sally Bercow over possible libel action by think tank MigrationWatch UK and their chairman Sir Andrew Green which was later dropped.

He has been a guest on the Remainiacs podcast several times in 2019, and has used his expertise to explain aspects of United Kingdom constitutional law as they relate to Brexit and the 2019 British prorogation controversy.