Who are the Big 4 of Johns Hopkins?

The Big Four of Johns Hopkins

At the turn of the 20th century, a quiet revolution was taking place in American medicine—and it was centered at The Johns Hopkins Hospital and Medical School. At the heart of this transformation stood four pioneering physicians, collectively known as “the Big Four.” Their vision, intellect, and relentless pursuit of scientific rigor reshaped medical education and clinical practice in the United States.

Sir William Osler, often called the father of modern medicine, brought a humane, bedside approach to patient care and authored the influential textbook *The Principles and Practice of Medicine*. His emphasis on observation and teaching changed how doctors learned and practiced.

In surgery, William Stewart Halsted was a towering innovator. He introduced radical mastectomy for breast cancer, pioneered the use of rubber gloves (thanks to his nurse, later wife, Caroline Hampton), and established the first surgical residency program—forever changing how surgeons were trained.

William Henry Welch, a pathologist and founding dean of the medical school, brought the rigor of laboratory science to American medicine. He helped establish the first public health school in the U.S. at Johns Hopkins, cementing the link between research, clinical practice, and population health.

Completing the quartet was Howard Atwood Kelly, a trailblazer in obstetrics and gynecology. He developed new surgical techniques, championed the use of X-rays in diagnosis, and insisted on treating women’s health with both scientific and ethical seriousness.

Together, these four men not only built a world-class institution but redefined what a physician should be: a scientist, a teacher, and a dedicated healer. Their legacy lives on in medical schools and hospitals across the country—captured forever in that iconic photograph of four men who changed medicine.