Davis was born in Suva, Fiji, the elder son of the Reverend Peter Davis, who served as President of the Methodist Church in Fiji and later as New South Wales Moderator of the Uniting Church in Australia. He spent his early years on the island of Lakeba in the Lau Group and attended Buca District School in Savusavu and Drasa Avenue School in Lautoka before being sent as a boarder to Newington College in Sydney from 1966 to 1971.
After completing his schooling, Davis began a career in journalism working in Britain and Australia. He reported for the BBC External Services and World Service News, the ABC, and the Macquarie Radio Network before transitioning to television.
Davis joined the Seven Network in Sydney in 1981 as a news reporter. In 1983 he moved to the Nine Network and joined the staff of the weekly current affairs program Sunday, where he remained until 1994. For the following decade he contributed occasionally to Sunday and also worked for Witness on the Seven Network, Dateline on SBS, and Foreign Correspondent on the ABC. In 2004, Davis returned to Sunday full-time and stayed until August 2006.
In 2012, Davis was engaged as host of The Great Divide, a weekly political discussion program on the Southern Cross Austereo television network.
Davis co-founded Grubstreet Media in 2007. The company produced the 2007 and 2008 Asia Pacific Screen Awards and associated programming for Queensland Events and CNN International, and conceived the First Australians Business Awards for the Australian Indigenous Chamber of Commerce. Grubstreet also produced television documentaries and commercials, including the 2011 national television and cinema campaign "Australian Mining. This is Our Story" for Lawrence Creative and the Minerals Council of Australia.
Davis has served as a columnist for the Fiji Sun. He has written regularly for The Australian and contributed to The Bulletin, The Sydney Morning Herald, the Herald Sun, and the Fiji Times. He also maintained the blog Grubsheet Feejee.
Davis has won several notable journalism awards. In 1995 he received the Walkley Award for Best Investigative Report for an investigation into commercial infiltration of the Australian Broadcasting Corporation. In 1994 he won a Logie Award for "Ships of Shame," a report on the state of world shipping. His 2002 report Silent Witnesses, which examined child abuse cases in the Jehovah's Witnesses organisation, won a New York Festivals Award in the United States. In 2004 he received an award from the Australian Council of Deans of Education for the Sunday program "Cash Cow Campuses," which exposed a plagiarism scandal at the University of Newcastle, and a National Press Club Excellence in Health Award for the Sunday investigation "Killer Hospitals." He also holds a Michael Daley Award for science reporting.
Davis has served as a judge of the Walkley Awards and the Qantas New Zealand Media Awards, and was a member of the national panel that reviewed the Australian Journalists' Code of Ethics. In addition to his journalism work, Davis has been a consultant to the Washington-based global communications company Qorvis on its Fiji account.