Following his discharge from Butler in 1886, Halsted moved to Baltimore, Maryland, to join his friend William Welch in organizing and launching the new Johns Hopkins Hospital. Halsted began working in Welch's experimental laboratory, and he presented a paper at Harvard Medical School. Soon thereafter, he was readmitted to Butler Hospital and remained there for nine months. He returned to Baltimore thereafter. When Johns Hopkins University Hospital opened in May 1889, he became Head of the Outpatient Department, acting Surgeon to the hospital, and Associate Professor of Surgery after being recommended by Welch when the first choice for the position fell through. These lesser positions alluded to the fact that the administration was still worried about Halsted's past cocaine addiction. In 1890, he was appointed Surgeon-in-Chief of the hospital. In 1892, Halsted joined Welch, William Osler, and Howard Kelly in founding the Johns Hopkins School of Medicine, and was appointed its first Professor of Surgery. Compared to his teaching in New York, Halsted's teaching was declining. He would pay attention to specific students and ignore the rest. But, he would also give certain residents that worked under him unprecedented learning experiences because of the amount of responsibility he awarded them. During these years at Johns Hopkins, he is credited with multiple achievements in the surgical world.