Greta Jean (Price) Dewar was born 23 May 1922 in Moncton, New Brunswick. Daughter of Lawrence Price and Beatrice Storey, Jean moved to Saint John, New Brunswick with her parents sometime prior to 1940. She attended Saint John High School and completed a one year course in the Department of Home Economics at the Saint John Vocational School, graduating in 1941.

Jean attended the Saint John General Hospital School of Nursing. During her studies she met her husband, George Dewar, who was completing his internship year of medical school at the Saint John General Hospital. In May 1944, Jean was granted a leave of absence from her nursing studies for the duration of the war. Jean would later go on to complete her nursing training in 1946.

On 7 June 1944, Jean married Dr. George Dewar at Germain St. Baptist Church in Saint John. The couple moved to Bedeque, Prince Edward Island in 1946 where George established his medical practice. By June of 1947, the couple had moved to Main Street, O'Leary where George took over Dr. Muncey Tanton's large medical practice.

Jean and George had two children: Elizabeth Ellen (b. 6 July 1950) and Brian Lawrence (b. 4 July 1955). In addition to being a mother of two and wife of a busy doctor and politician, Jean was an active member of her local community. She was a founding member of the Ladies Auxiliary of the O'Leary Community Hospital (est. in 1956) and served in several capacities over the years, including as president from 1959-1960 and 1977-1978. Jean was also treasurer of the O'Leary Baptist Senior Women's Missionary Society. She also continued to study and take courses in health, nursing, and education throughout her adult life. Jean was involved in a number of committees and groups dedicated to seniors' health issues, such as the Long Term Care Committee, the Senior Information/Education Sub-Committee, the Atlantic Seniors Networking Project, and the West Prince Senior Assessment Steering Committee. Jean was also a strong supporter of culture and cultural activities in PEI and was awarded the Lescarbot Award jointly with her husband in 1992.

Jean Dewar died 27 February 2008 at Whisperwood Villa in Charlottetown. She was buried with her late husband George in the Brudenell Cemetery.