Kolff and his family immigrated to Cleveland, Ohio, in 1950, where he became head of the department of artificial organs and professor of clinical investigation at the Cleveland Clinic Foundation. There he began work on an artificial heart, and in 1957 the implantation of a totally artificial heart in the chest of an animal was accomplished for the first time. Kolff left Cleveland in 1967 to continue his work on the artificial heart. He arrived at the University of Utah and became director of the Institute for Biomedical Engineering and its artificial organs division. Under Kolff's leadership, the University of Utah has since developed one of the world's leading artificial organ research centers. In 1982, under his supervision, the first fully artificial heart was implanted in a human patient, Barney Clark. Kolff retired in 1986 on his 75th birthday but continues to work part-time.