Sydney Lance Townsend was born in Geelong, Victoria, on 17 December 1912. Following completion of his medical degree at the University of Melbourne in 1935 he worked as a resident medical officer at Bendigo and Base Hospital, the Royal Women's Hospital and the Tennant Creek Hospital (NT) between 1936 and 1938 inclusive. In 1939, whilst working at the West Middlesex Hospital (UK), he obtained the Diploma of Tropical Medicine and Hygiene and became a member of the Royal College of Obsetricians and Gynaecologists. Between 1939 and 1945 he served with the Royal Navy in the Mediterranean and Eastern areas, was awarded King's Commendation and was demobilised as surgeon commander. Between 1948 and 1963 he served in the Volunteer Reserve with the Royal Australian Navy and was promoted to surgeon captain.

Following his war service he returned to the West Middlesex Hospital in the UK, working there in 1946 and 1947. During that time he became a fellow of the Royal College of Surgeons of Edinburgh and, after returning to Australia in 1948, became a fellow of the Royal Australasian College of Surgeons. He was appointed professor of obstetrics and gynaecology at the University of Melbourne in 1950 and became a fellow of the Royal College of Obstetricians and Gynaecologists in 1952, obtained his MD at the University of Melbourne for research on hypertension in pregnancy, and became an honorary fellow of the Royal College of Physicians and Surgeons of Canada, the College of Obstetricians and Gynaecologists of South Africa and the American College of Obstetricians and Gynaecologists. In 1977 he was elected a fellow of the American College of Surgeons.

Following his retirement he became a fellow of the Royal Australian College of Medical Administrators, was awarded the Master of Gynaecology and Obstetrics at the University of Melbourne and obtained the Doctor of Laws (honoris causa) at both Monash University and the University of Melbourne. In addition he was awarded the fellowship of the Royal Australasian College of Physicians and became a fellow of the Royal Australian College of General Practitioners.

As professor of obstetrics and gynaecology at the University of Melbourne he built a department which led the world in many aspects of obstetrical and gynaecological care. As dean of the faculty of medicine between 1971 and 1977 he was a forceful leader and played a major role in the affairs of the University of Melbourne. He was a member of the University Council from 17 December 1971 until his death. In 1978 he was appointed assistant vice-chancellor and contributed to the development of staffing and budgetary policies within the university. He was also a significant contributor and tireless worker for a number of organisations including the Royal Women's Hospital, the Austin Hospital of which he was President, the Victorian Bush Nursing Association, the Masonic Lodge of Victoria, the National Health and Medical Research Council, the World Health Organisation, the Maternal Health Committee and the Victorian Cytology Service. He was co-author of the Syme-Townsend report on Victorian Health Services and was appointed foundation chairman of the Health Advisory Council of the Health Commission of Victoria, a post he held until his death.

Internationally, he was a member of the executive committee of the International Federation of Obstetrics and Gynaecology from 1964 to 1979 and served as vice-president. In 1980 he was appointed consultant obstetrician for the World Health Organisation and was responsible for examination of the Eastern Mediterranean region. He also held many appointments in addition as visiting professor in overseas medical schools. In all of his appointments his energy and enthusiasm were obvious to those with whom he worked and his influence on the speciality of obstetrics and gynaecology both in Australia and elsewhere was profound. His sense of fulfilment never diminished his devotion to duties ahead for his commitment was based on the foundation of perception well in advance of many of his colleagues. His international reputation as a speaker, his organisational ability, his teaching prowess, and his unaffected ability to communicate and impart wisdom to all who sought his ever-willing assistance clearly attested to his overall capacity.