John Kirklin, former chairman of the department of surgery at the University of Alabama at Birmingham, revolutionised cardiovascular surgery through his development and refinement of the heart-lung machine. Throughout his life, he sought new methods and techniques to improve the care of patients. Born in Muncie, Indiana, on 5 August 1917, his father was director of radiology at the Mayo Clinic. John earned his bachelor’s degree from the University of Minnesota in 1938. He then went on to Harvard, where he gained his medical degree in 1942. He completed an internship at the University of Pennsylvania Hospital in Philadelphia and then served as a fellow in surgery at the Mayo Clinic. From 1944 to 1946 he served in the US Army, with the rank of Captain. He then spent six months at the Boston Children’s Hospital. In 1950, he joined the staff of the Mayo Clinic, pioneering the development of cardiovascular surgery and performing the first operations for a range of congenital heart malformations. He also modified the Gibbon machine, improving the original pumping and oxygenator system, and performed the world’s first series of open-heart operations using a heart-lung machine. At Mayo he became chairman of the department of surgery, and trained the next generation of cardiovascular surgeons from all over the world. In 1966, Kirklin joined the faculty of the University of Alabama at Birmingham (UAB) as chairman of the department of surgery and the surgeon in chief for UAB Hospital. He held these positions until 1982, during which time he built one of the most prestigious cardiovascular surgical programmes in the world. He retired from surgery in 1989. He wrote more than more than 700 publications, but he often stated that his greatest contribution was his textbook, *Cardiac surgery: morphology, diagnostic criteria, natural history, techniques, results, and indications* (Churchill Livingstone, 1956), which remains an important reference text in the field. He also served on multiple editorial boards and served as editor of *The Journal of Thoracic and Cardiovascular Surgery.* He received many awards, including the American Heart Association research achievement award (in 1976), the Rudolph Matas award in vascular surgery, the Rene Leriche prize of the International Society of Surgery and the American Surgical Association medallion for scientific achievement. In 1972 he was awarded the Lister medal by the College. Many universities awarded him honorary degrees, including the Hamline University, St Paul, Minnesota, Indiana University, Georgetown University, the University of Munich, Germany, and Bordeau and Marseille Universities, France. He was a member of more than 60 local, state, national and international associations and scientific societies, including the American Association for Thoracic Surgery (serving as President from 1978 to 1979), the American College of Cardiology, the American Heart Association, the American College of Surgeons and the National Academy of Sciences Institute of Medicine. His wife Margaret Katherine was a physician. They had two sons and a daughter. The Kirklins have continued the medical tradition: his son is a cardiac surgeon and director of cardiothoracic transplantation at UAB, and his grandson is a medical student at UAB. John died on 21 April 2004 from complications from a head injury that occurred in January. The new clinic at Birmingham Alabama, designed by the world-famous architect I M Pei, is named in his honour.