Bach also served as Deputy Leader of the Opposition in the Legislative Council, and as a frontbencher in the Shadow Cabinets of Michael O'Brien, Matthew Guy, and John Pesutto.

[5] After graduating, Bach worked as a schoolteacher in the United Kingdom and as a Ministerial Advisor to Mary Wooldridge when she was the Minister for Community Services, Mental Health, and Women's Affairs in the Baillieu Government.

[6] Bach then worked as a senior leader, staff board representative and teacher of History and Politics at Carey Baptist Grammar School.

[6] Bach won the Liberal Party's nomination to fill the vacancy caused by the resignation of Mary Wooldridge, and was sworn in as Member for Eastern Metropolitan Region in March 2020.

[8] In the lead up to the 2022 election, Bach also served as the Shadow Minister for Transport Infrastructure and was a vocal opponent of the Andrews Government's Suburban Rail Loop, citing inadequate planning and significant cost overruns.