[4] Griffin was elected on 8 April 2017 at the Manly state by-election held to replace the previous member, former premier of New South Wales Mike Baird.

Griffin went to school at St Mary's Cathedral College, and in 2006 was one of the first students to enrol at the Sydney campus of the University of Notre Dame Australia, from which he graduated with a Bachelor of Arts in 2008.

His mother, Cathy Griffin, was a major in the Australian Army, and also served one term as a councillor in Manly, albeit as a member of the NSW Greens.

Former Australian Foreign Minister, Julie Bishop[11] is also named as a mentor alongside Chief Executive Officer of GB News, Angelos Frangopolous[12].

As Environment Minister, Griffin implemented a number of historic reforms including the banning of problematic single use plastics and the largest ever acquisition of land for a New South Wales National Park.