Jean Halliday MacKay, was born in 1920, the daughter of James Franklin Halliday and his wife Emeline Catherine Moore MacInnes. She was raised in Eldon, a small community in Eastern Prince Edward Island. She received her early education in the Eldon one-room school and Prince of Wales College and Normal School in Charlottetown. She obtained a First-Class Teacher's Certificate in 1938. Jean taught in rural schools in Prince Edward Island.

In 1942, she joined the Women's Royal Canadian Naval Service (WRCNS or Wrens) and served for over two years.he earned a Bachelors of Science degree in Home Economics from Mount Allison University in Sackville, New Brunswick in 1950. Subsequently, she worked as assistant dietitian at the Provincial Sanatorium in Charlottetown, taught high school in Sackville, New Brunswick and worked as an Extension Home Economist in Western Canada. In 1956, Jean began studies at Michigan State University, where she received an MSc and PhD. She then taught at the University of Winnipeg in Manitoba.

After she received her PhD, Jean married Wendell MacKay. While Wendell studied law at Dalhousie, Jean taught in the Home Economics Program at Mount Saint Vincent University in Halifax. When they returned to Prince Edward Island, she taught at Prince of Wales College.

Their family was enlarged when, son Kenneth and daughter Flora joined them. In 1969, Jean joined the faculty at the University of Prince Edward Island where she taught courses in Home Economics until her retirement in 1986.

She was author of The Home Place: Life in Rural Prince Edward Island in the 1920s and 30s published in 1999. She was active in the Prince Edward Island Home Economics Association and the Belfast Historical Society.

Jean died at her home in Charlottetown on February 13, 2004, at the age of 83. She was predeceased by her husband Wendall and son Kenneth. She left surviving her daughter Flora (husband Paul Wood), and three grandchildren.