Billing has starred in many television shows and had main roles on Bad Cop, Bad Cop, Dossa and Joe and Hell Has Harbour Views. 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. In 2000 he featured in the film The Dish, portraying the Mayor of Parkes in a comedy about the moon landings. He also appeared as part of the ensemble on the 2006 season of Thank God You're Here. He has had a guest role on All Saints.