Ernsting was born in Woolwich, London on 21 April 1928, and educated at Chislehurst and Sidcup Grammar School for Boys.

[4] On retiring from the RAF, Ernsting became a visiting professor at King's College London (KCL), where he taught a human and applied physiology Master of Science course.

[1] In 1998, Ernsting was appointed Head of the Human Physiology and Aerospace Medicine Group of the Guy's, King's and St Thomas's School of Biomedical Sciences.

[1] On 1 January 1958,[6] the then Acting Squadron Leader Ernsting,[6] was appointed an Officer of the Order of the British Empire for his work in connection with the Lightning and Canberra aircraft.

[1] He was appointed Companion of the Order of the Bath on 31 December 1991,[7] on completion of his tenure as Commandant of the RAF Institute of Aviation.

[1] In May 2008 Ernsting was awarded the title of honoris causa by PUCRS, Porto Alegre, Brazil in recognition of his distinguished contribution to the field of Aerospace Physiology.