In 1979, Anionwu became the United Kingdom's first sickle-cell and thalassemia nurse specialist, helping establish the Brent Sickle Cell and Thalassaemia Counselling centre with Consultant Haematologist Dr Milica Brozovic. In 1998, by then a Professor of Nursing, Anionwu created the Mary Seacole Centre for Nursing Practice at the University of West London. She holds a PhD, was appointed a Dame Commander of the Order of the British Empire and is a Fellow of the Royal College of Nursing (RCN). She retired in 2007, and in 2016 she published her memoirs, "Mixed Blessings from a Cambridge Union".