Gregg joined Ulster Television at the age of 19 in 1959, starting as an announcer and later becoming a local news reporter and presenter of "Roundabout". She was reputed to be the youngest current affairs presenter in the United Kingdom. She moved to England in 1963, where worked at an advertising agency before moving to Anglia Television, in Norwich, to present a current affairs programme. She moved to London to work for the BBC, first as a continuity announcer, and later becoming a news reader on national television.