Bull first ran for the
City of Bayswater council in 2015. He said he was interested in local politics because he wanted better road safety, accountability, trees and nature playgrounds. He was elected as a councillor for the west ward in October that year. Bull is a member of the
Labor Party's
Left faction and is aligned with the
United Workers Union. He was elected mayor by the Bayswater council unopposed after the October 2017 local government election, succeeding Barry McKenna. He was re-elected following the October 2019 local government election. Following the October 2021 local government election, Bull was unexpectedly defeated as mayor by
Labor Right member Filomena Piffaretti, who received the support of independent and Liberal-aligned councillors. Bull was
preselected to be the Labor Party's candidate to replace Baker in the
electoral district of Maylands. In March 2025, he won Maylands with about a 71 percent two-party-preferred vote. ==Personal life==