Jenny Seagrove's theatre work includes the title role in Jane Eyre at Chichester Festival Theatre (1986); Ilona in The Guardsman at Theatr Clwyd (1992); and Bett in King Lear in New York, again at Chichester (1992).
She played opposite Tom Conti in Present Laughter at the Globe Theatre (1993); Annie Sullivan in The Miracle Worker at the Comedy Theatre (1994); Dead Guilty with Hayley Mills at the Apollo Theatre (1995); Hurlyburly for the Peter Hall Company when the production transferred from the Old Vic to the Queen's Theatre (1997); co-starred with Martin Shaw in the Parisian thriller Vertigo (Theatre Royal Windsor October 1998) and then with Anthony Andrews (also Windsor,1998).
In 2000 she appeared in Brief Encounter at the Lyric Theatre; followed by Neil Simon's The Female Odd Couple at the Apollo (2001). Again at the Lyric Theatre in 2002 she played the title role in Somerset Maugham's The Constant Wife, followed by a revival of David Hare's The Secret Rapture in 2003, and The Night of the Iguana two years later in 2005.
Coming in to the West End from a UK tour, she played Leslie Crosbie in Maugham's The Letter at Wyndham's Theatre (2007), again co-starring with Anthony Andrews . In December 2007 she went on to play Marion Brewster-Wright in the Garrick Theatre revival of Alan Ayckbourn's dark, three-act comedy Absurd Person Singular .
Seagrove's first major international film appearance was in the 1983 release, Local Hero in which she played a mysterious environmentalist with webbed feet, after which she had roles in a number of films including Nate and Hayes opposite Tommy Lee Jones and Appointment with Death. One of her few lead starring roles was in 1990s The Guardian, in which she played a villain.
In the mid-1980s, Seagrove starred in two American-produced television miniseries based upon the novels of Barbara Taylor Bradford: as Emma Harte in A Woman of Substance (1984) and Paula Fairley in Hold the Dream (1986). In 1991, she portrayed stage actress Lillie Langtry in a made-for-UK television adaptation of the Sherlock Holmes story, Incident at Victoria Falls. Also, in 1985 she starred as the female lead, Melanie James, in the movie Magic Moments, together with John Shea, who played the magician Troy Gardner whom she falls in love with. Most of Seagrove's filmed work since 1990 has been for television. Since 2001, she has appeared as Jo Mills in the series Judge John Deed.