Her father, originally from County Antrim, had arrived in Victoria in 1855, and became a successful land agent and auctioneer in Port Fairy.

[2] Her mother died when she was a few months old, and her father remarried Millie's maternal aunt Jane Ellen Arnold.

She was first introduced to politician Alexander Peacock in 1899, when her family hosted members of the Australian Natives' Association during a conference.

Lady Peacock only gave one speech in parliament, on the third reading of the Factories Act Bill.

[7] She retired from politics at the end of her term in 1935, saying that representing a country electorate in parliament was no place for a woman.