In November 1963, he was the "pool" reporter in Hyannis Port at the Kennedy compound in the aftermath of John F. Kennedy's assassination. His reporting was noticed by WCBS, who hired him in 1964. He soon became weekend anchorman and backup weekday anchor behind Robert Trout, who was doing double duty at the station and at CBS News. Jensen didn't take too long to make an impact, winning notice for his coverage of Robert F. Kennedy's Senate campaign soon after he arrived in New York. When Trout left for a network assignment in Europe, Jensen succeeded him as WCBS' main anchor. He was the face of the WCBS newsroom for the next three decades.