In teaching and in research, Blalock paved the way for a new generation of surgeons. Students of Blalock appreciated his unique ability to bring out the best of them. As chief of surgery at Hopkins, Blalock trained 38 chief residents, as well as 9 chairmen of departments, 10 division chiefs, and many others. Many of Blalock's students went on to become cardiovascular surgeons themselves and rose to high levels of importance in the surgical world. His colleague and lifelong friend, Tinsley Harrison spoke about Blalock's ability to teach saying, "A teacher is an individual who has the capacity to influence the horizons of his pupils. Al has had that capacity all of his life."