After completing a clinical research fellowship in anesthesia at Harvard Medical School, Lasagna joined the faculty of Johns Hopkins University in 1954, where he established the first ever clinical pharmacology department. Lasagna taught medicine and pharmacology at Johns Hopkins until 1970, when he accepted the position as the first chairman of the Department of Pharmacology and Toxicology at the University of Rochester's, School of Medicine and Dentistry, which he held for the next decade (1970–1980). Early in his fourteen-year career at Rochester, Lasagna founded the Center for the Study of Drug Development, later called the Tufts Center for the Study of Drug Development.
After completing a clinical research fellowship in anesthesia at Harvard Medical School, Lasagna joined Johns Hopkins University's faculty in 1954 and established the first-ever clinical pharmacology department. He taught medicine and pharmacology there until 1970 when he became the inaugural chairman of the Department of Pharmacology and Toxicology at the University of Rochester's School of Medicine and Dentistry, a position he held for ten years (1970–1980). Early in his fourteen-year career at Rochester, Lasagna founded the Center for the Study of Drug Development, which was later renamed the Tufts Center for the Study of Drug Development.