Her parents met while Jesse was stationed in New Zealand, after having contracted malaria serving at Guadalcanal.
Jesse and Ellanora arrived in New Zealand in 1948, with 4-year-old Margaret and baby Wyatt, and settled at Whareama, where Jesse worked as a shepherd.
Dr Milne said the family lived in a small cottage "with no power", and young Margaret walked across a swing bridge over the river every morning to Whareama School.
The family later relocated to Pirinoa, where Margaret attended school before boarding at St Matthew's for much of her college years.
After finishing college, Margaret worked as a nanny to the Vestey family (of the meat trading company Vestey Brothers) in London, and obtained her teaching qualification on returning to New Zealand, later working at Featherston School.
She met Dr Milne in Martinborough while he was setting up Martinborough Vineyard, and the couple married in 1982.
The Milnes lived in Greytown while their five children were young, and moved to Wellington in 1999, returning to Wairarapa in 2010. Dr Milne said his wife was happiest when she was out walking, renovating and painting various family homes, or working in the garden - in fact, as her brother mentioned in his eulogy, she had requested to be buried in her "North Carolina" T-shirt and gardening trousers, and with a pair of secateurs.
Two of her greatest passions were quilting - in the traditional American style - and embroidery, with a collection of her work housed in the Aratoi exhibition 400 Shades of DMC, shortly before her death.
"It was a magnificent obsession: most nights, she'd tell the kids to go to their rooms, and she'd settle down for an hour with her embroidery," Dr Milne said.
"She was so talented - that exhibition was world class." Dr Milne describes Margaret as an "independent spirit", intelligent and well-read, and fiercely devoted to her family.
"She had her own views and wasn't afraid to vocalise them."
She is survived by Dr Milne, daughters Ella, Sophie, Christina and Sally, son Bartholomew, and grandchildren Connor and Maia.