McKittrick began his career as a reporter for the East Antrim Times. He joined the Irish Times in 1973 as a reporter in Belfast, becoming Northern editor in 1976 and London editor in 1981. He worked briefly for BBC Northern Ireland between 1985 and 1986, before joining The Independent. He has since worked as the paper's Irish correspondent.
Widely recognised by those with a similar point-of-view for the scope of his knowledge and the balance of his reporting on Northern Ireland, he contributes regularly to overseas newspapers and journals. His many awards include the Christopher Ewart-Biggs Memorial Prize for the promotion of peace and understanding in Northern Ireland, 1989 and 2001; Correspondent of the Year, 1999; and the 2000 Orwell Prize for Journalism.