Sissons joined ITN in 1964, working his way up to the role of journalist. He was wounded by gunfire whilst covering the Biafran War in 1968, sustaining severe nerve damage in his left leg. After recovering from his injuries, he became ITN's Industrial Editor, covering many high-profile disputes during the 1970s. On 6 September 1976, Sissons joined the list of presenters of ITN's lunchtime ITN News at One bulletin, alternating with Leonard Parkin. He also co-presented ITN's 1983 General Election Night programmes (with Sir Alastair Burnet and Martyn Lewis) and in 1987 (with Burnet and Alastair Stewart).