John Celermajer was born in Lvov, Poland. His family was tragically affected by, and forced to flee from the Holocaust. Largely without formal education or local language skills, John quickly achieved academic success in his new, but temporary home in Paris. On emigrating to Australia, he again established his academic credentials with remarkable success at Randwick Boy's High School in Sydney.

Medical School at the University of Sydney presented no difficulties. Following junior residency at Royal Prince Alfred Hospital, John joined the resident staff at The Children's Hospital, Camperdown where his brilliance further flourished. He established himself as a redoubtable physician, much respected by his colleagues. A penchant for fine cars, food and, later, a deep interest in art and antiques found their footholds during this time and these would subsequently give much pleasure to John, his family and friends. John soon developed a special interest in the new subspecialty area of paediatric cardiology (1965 and 1966), which seemed to suit his talents.

The family spent 1967 and 1968 in Baltimore, USA where John was senior fellow in paediatric cardiology at The Johns Hopkins Hospital supported by a National Heart Foundation of Australia Fellowship. On his return to Australia in 1968, John took up one of the first subspecialist positions at the Children's Hospital, Camperdown as a paediatric cardiologist and soon after took on the position of director of the Adolph Basser Institute of Cardiology, a position he held until his death. Together with his colleagues in surgery, radiology and anaesthetics, John established a unit of national and international reputation in paediatric cardiology, with foundations of excellence which continue to drive it.

John held many representative positions on local and overseas bodies, including the World Health Organization and the International Society of Cardiology. He was widely sought as a reviewer and was part of the steering committee for the Third World Congress of Paediatric Cardiology in 1989, which he sadly was unable to attend. John provided clinical services not only to the children of Australia, but also cared for cardiac patients from many Pacific rim countries and jointly established a programme of clinics and subsequent care of paediatric cardiac patients from Papua New Guinea. He also acted as an examiner for The Royal Australasian College of Physicians. John also valued highly his role as a teacher. His skills in this area are widely attested to by the many adult cardiology and paediatric trainees who spent time in his clinics or rotating through the cardiology unit.

A special place was devoted by John for his family, and their time together was carefully guarded. John's close and radiant relationship with Tina was a source of great strength, and David and Dany provided much reason for pride with their personal and academic achievements. John pursued excellence in all avenues of professional and personal life. His ability for clear thought and commitment to teaching, tempered by gentleness and good humour, resulted in the affection, admiration and respect of his colleagues, students and patients. Those counted amongst his friends were specially blessed. A memorial service was held in the Maclaurin Hall at the University of Sydney on 21 April 1990. The large gathering heard witness to a remarkable and many faceted man whose legacy, the melding of quality, integrity, intellectual achievement and caring, will be valued by all those who came in contact with him.