[1] Prior to entering parliament Griffin worked as a public servant, union organiser and political staffer.

[5] In March 2015, former City of Port Phillip Mayor Julian Hill was preselected unopposed to contest Bruce for the Labor Party.

Griffin began working as a lobbyist after leaving parliament, joining The Civic Group.

As of 2021[update] he was listed on both the Victorian and federal registers of lobbyists and had been engaged to lobby on behalf of the owners of the Maddingley coal mine.

[6] In 2024, he and his former ministerial colleague Stephen Conroy were reported to be among the most influential lobbyists in Canberra, following the ALP's return to power at the 2022 election.

[7] Griffin was described in 2021 as "a key powerbroker within Victorian Labor" who had been crucial in brokering a factional truce that allowed Sam Rae to win preselection for the seat of Hawke.