O'Callaghan played "Carrie Rawlins" in Bedknobs and Broomsticks (1971), where she starred opposite Angela Lansbury and David Tomlinson.
O'Callaghan attended university in 2000, and in 2004 it was reported that she had given up acting to become a child Psychologist. She commented "Four years ago, I decided to go to university and am now training to be a child Psychologist. I just wanted to do something that was more fulfilling." However, O'Callaghan has appeared on television since this time, in the 2005 documentary The 100 Greatest Family Films, where she discussed the movie Bedknobs and Broomsticks, along with co-stars Angela Lansbury and Ian Weighill, who played Charlie Rawlins in the film.
More recently she is known for her role as Andrea Price—the "boozy" mother of Natalie Evans (Lucy Speed)—in the BBC soap opera EastEnders (1994–1995; 1999). This was O'Callaghan's second role in the soap, having previously played Stella — the mistress of Ashraf Karim — from 1989-90.
