Nesta Summerhayes (nee Mackey) was born in Hobart, Tasmania. Already a trained nursing sister, she joined the Royal Australian Army Nursing Corps (RAANC) in April 1952. Working initially in a camp hospital in Australia, Nesta arrived in Japan in November 1953, where she worked as a nursing sister at the British Commonwealth General Hospital (BCGH) in Kure. This was the main base hospital for British Commonwealth casualties during the Korean War and in the post-armistice period.
Between February and May 1954 Nesta served at the British Commonwealth Communications Zone Medical Unit (BCCZMU) in Seoul, Korea. Although casualties at the BCCZMU were reduced after the armistice period, medical staff remained busy tending to casualties who suffered illnesses such as frostbite, caused by the freezing Korean winter. Many patients also suffered burns from the kerosene heaters they used in their tents to keep warm.
After serving in Korea, Nesta returned to Japan, again working at the BCGH in Kure. Between February and May 1955 Nesta worked as Senior Sister at the Casualty Dressing Station in Tokyo, for the most part caring for soldiers on recreational leave.
On her return to Australia in July 1955, Nesta continued her career in the RAANC, working at a military hospital in Brighton. In April 1957, with her initial period of engagement complete, Nesta discharged from the RAANC. She continued her civilian nursing career working at Launceston General Hospital in Accident and Emergency, then at St Luke's Hospital and continued on in varied arms of the profession until her retirement in 1991.