Halsted returned to New York in 1880 and for the next six years led an extraordinarily vigorous and energetic life. Like when Halsted visited Europe, it was an opportune time for Halsted's involvement because surgery was on the brink of various important discoveries. He operated at multiple hospitals including the Chambers Street Hospital, College of Physicians and Surgeons where he was Assistant Demonstrator in Anatomy, Charity Hospital, Bellevue Hospital and Roosevelt Hospital (currently Mount Sinai West) where he was a visiting physician at all three, and Emigrant Hospital where he was Surgeon-in-Chief. At Bellevue Hospital, he convinced the hospital to erect a tent that was used as his surgical area where he could practice the idea of antiseptic surgery. This project cost $10,000 at the time. Halsted also started teaching, but he greatly strayed from classical teaching methods. He reformed the classroom by creating a more hands-on experience coupled with theory for his students who were generally at the top of their classes. He was an extremely popular, inspiring and charismatic teacher due to this. In 1882 he performed one of the first gallbladder operations in the United States, a cholecystotomy performed on his mother on the kitchen table at 2 am in which he removed seven gallstones. His mother completely recovered. Halsted also performed one of the first emergency blood transfusions in the United States. He had been called to see his sister after she had given birth. He found her moribund from blood loss, and in a bold move withdrew his own blood, transfused his blood into his sister, and then operated on her to save her life. Because of these operations, Halsted became known for being bold, and his reputation as a surgeon was gradually increasing.