He became widely known for his role as organised-crime boss “Aussie Bob” Trimbole in the TV series Underbelly.

After a short period at university doing a science degree, he dropped out and got a job at Inland Revenue.

After three years he moved into advertising, joining Auckland agencies Jacka Brown and later, McCann Erickson.

Billing also had a recurring role on Blue Heelers as Senior Constable Ian Goss, on Always Greener as Eddie McGill, in Packed to the Rafters as Ron Barrett, and in Under the Mountain.

[2] In 2009, Billing played Griffith drug lord Robert Trimbole in the high-rating drama series Underbelly: A Tale of Two Cities, starring alongside Matthew Newton.

Billing played the part of Chief Dufflepud in the 2010 film The Chronicles of Narnia: The Voyage of the Dawn Treader as well as a recurring character in the Nine Network police drama Cops L.A.C..

[6] On 26 January 2015, Billing was awarded the Medal of the Order of Australia for "service to the performing arts, particularly as an actor, and to the community".