 He served on the Adelaide City Council as Councillor and Alderman from 1842

He won the seat of Noarlunga in the South Australian Legislative Council (then the only House) against Major O'Halloran in 1851 which he held to 1856.He won a Legislative Council seat in 1861, which he held until 1869 when he retired, a few days before parliament was prorogued.William Peacock married Elizabeth Everett, daughter of Joseph, another Bermondsey fellmonger, in 1816.