While a student at St Patrick's, he was editor of the school magazine, "Tuairim"; features writer for "Drogheda Independent", "Ipswich Evening" and "Meath Chronicle"; and hosted a radio show for Royal County Radio, a local pirate radio station. He started reporting for "The Weekender". Around the age of 20, he started as a rookie and advanced to chief reporter for Capitol Radio (now called FM104) in Dublin, Ireland. In 1990, Cumbers moved to the United Kingdom to work with a variety of British broadcasters, including ITN's Channel 4 News, Channel 4 Daily, Sky News, APTN, and the BBC. Cumbers worked both as a journalist and a producer. In the late 1990s, he retrained and became a cameraman as well, establishing Locum Productions with his wife and BBC journalist Louise Bevan, to supply camera crews to broadcasters. Among the stories Cumbers reported on were the 1989 death of Nicolae Ceaușescu during the Romanian Revolution; the 1990 release of Brian Keenan in Beirut, Lebanon; the late 1990s Drumcree conflict; the Good Friday Agreement and Omagh bombing in 1998, the Kursk submarine disaster in 2000, and the 2004 Madrid train bombings. He had also interviewed Muammar Gaddafi in Libya.