After graduation, Redgrave landed a succession of high-profile stage acting roles: in the 1988 stage production of Strindberg's Easter; in Lady Windermere's Fan in Belfast, Northern Ireland; as Emily in Thornton Wilder's Our Town; as Irina in a 1990 revival of Anton Chekhov's The Three Sisters in London's West End with her aunts Vanessa Redgrave and Lynn Redgrave; in 1993 with Colin Firth in Alexander Griboyedov's Chatsky at the Almeida Theatre, London; and in A Midsummer Night's Dream in 2001 at the Albery Theatre (now the Noël Coward Theatre), London, playing Titania alongside Dawn French as Bottom.

Redgrave also appeared as Eleanor in Roger Michell's The Buddha of Suburbia: a four-part adaptation of the ground-breaking novel of the same name by Hanif Kureishi and with a soundtrack written and performed specifically for the production by David Bowie.

[citation needed] Other prominent roles have included Francesca Rochester in Judge John Deed and Dee Stanton in Like Father, Like Son.

In 2007, she portrayed Lady Bertram in Mansfield Park and Sophie Wall in Waking the Dead, followed by a 2009 appearance in the series, Unforgiven, written by Sally Wainwright.

[8] From 2016 to 2018, Redgrave played former RAMC surgeon, Major Berenice Wolfe, in the popular BBC medical drama Holby City.

First appearing in "The Power of Three" (2012) with the Eleventh Doctor (Matt Smith), Kate is the commander-in-chief of the fictional military organisation UNIT, a role previously occupied by her father before his retirement.

Regrave also featured as Kate in a promo video for Doctor Who: Time Fracture, an immersive experience that began running in London in April 2021.