She made her cinema debut in the Scotland Yard film Gideon's Day (1958) as Sally, daughter of Jack Hawkins's Detective Inspector.

[11] She played a potential murder victim in Michael Powell's cult thriller Peeping Tom (1960) and appeared in Otto Preminger's Bunny Lake Is Missing (1965).

In the documentary on the film's DVD release, Massey mentioned that she originally auditioned for the much smaller role of the secretary Monica, a part for which Jean Marsh was cast.

She made her first small-screen appearance as Jacqueline in Green of the Year in October 1955,[12] and thereafter featured in dramas such as The Pallisers (1974), The Mayor of Casterbridge (1978), the 1979 adaptation of Rebecca (in which she starred with her ex-husband Jeremy Brett), The Cherry Orchard (1980), and Anna Karenina (1985).

She was the narrator of This Sceptred Isle on BBC Radio 4, a history of Britain from Roman times which ran for more than 300 fifteen-minute episodes.

[15] Michael Billington of The Guardian characterised her work as being informed by "stillness", such as in the National Theatre's production of Harold Pinter's A Kind of Alaska.

[6] In the New Year's Honours List published on 31 December 2004, she was created a Commander of the Order of the British Empire (CBE) for services to drama.

[17] Massey published an autobiography in 2006, Telling Some Tales, in which she revealed a difficult early life, including a distant relationship with her famous father and estrangement with her brother.

[20] At an August 1988 dinner party held at the home of their mutual friend, Joy Whitby,[9] she met Russian-born metallurgist Uri Andres, who had been based at Imperial College, London since 1975.