Carl was raised in Drexel Hill and attended Monsignor Bonner High for two years before transferring to Peekskill Military Academy in New York. In the summer of 1960, while he was still a student at Bonner, he qualified for the Olympic trials in the 200 meter butterfly and finished fifth. The following year, Carl broke the world record in the butterfly. In 1963, he entered the University of Michigan on a full swimming scholarship. At Michigan, he captured two N.C.A.A. titles and was an All-American in every event but the breast stroke. After a silver medal finish in the butterfly at the 1964 Olympic Games in Tokyo, Carl returned to the Olympics again, four years later. At the 1968 Olympics in Mexico City, he won the gold medal in the 200 yard butterfly in an upset victory over the great Mark Spitz.