She is known for her role as the character of Jo Mills in the long-running BBC drama series Judge John Deed (2001–7). Her credits as a voiceover artist include a series of Waitrose television advertisements.
Seagrove was born Jennifer Ann Seagrove in Kuala Lumpur, Malaya (now Malaysia) in 1957, to British parents, Pauline and Derek Seagrove. Her father ran an import-export firm, which afforded the family a privileged lifestyle. When Seagrove was less than a year old, her mother suffered a stroke, and was unable to care for her. Seagrove attended St Hilary's School in Godalming, Surrey, England from the age of nine.
After leaving school, Seagrove began attending acting classes and trained at the Bristol Old Vic Theatre School, in spite of her parents' wishes for her to have a career as a professional cook. Seagrove developed bulimia in her early adulthood, but recovered: "I could feel myself tearing my stomach, and I kind of pulled out of it," she said. "It was a very slow process."
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 London 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 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 played Marion Brewster-Wright in the Garrick Theatre revival of Alan Ayckbourn's dark, three-act comedy Absurd Person Singular.
In early 2014, she appeared as Julia in a revival of Noël Coward's Fallen Angels. The production was produced by her husband Bill Kenwright and also starred Sara Crowe.
Seagrove starred alongside Rupert Everett in the Academy Award-winning short film A Shocking Accident (1982), directed by James Scott. Her first major film appearance was in Local Hero (1983) in which she played a mysterious environmentalist with webbed feet. Roles in a number of films including Nate and Hayes (aka, Savage Islands, 1983) opposite Tommy Lee Jones and Appointment with Death (1988) followed. One of her lead starring roles was in The Guardian (1990) directed by William Friedkin, in which she played an evil babysitter.
Seagrove first came to mass public attention in the 10-episode series of the BBC production Diana (1984) adapted from an R. F. Delderfield novel, in which she played the title role as the adult Diana Gaylord-Sutton (the child having been played in the first two episodes by Patsy Kensit). Seagrove starred in two American-produced television miniseries based upon the first novels of Barbara Taylor Bradford: as Emma Harte in A Woman of Substance (1984) and Paula Fairley in Hold the Dream (1986). She portrayed stage actress Lillie Langtry in Incident at Victoria Falls (1992), a UK made-for-television film. As the female lead, Melanie James in the film Magic Moments (1989), she starred with John Shea, who played the magician Troy Gardner with whom she falls in love.
Seagrove, along with Simon Cowell, presented Wildlife SOS (1997), a documentary series about the work of dedicated animal lovers who save injured and orphaned wild animals brought into their sanctuary.
Most of Seagrove's filmed work since 1990 has been for television. Between 2001 and 2007, she appeared as QC Jo Mills in the series Judge John Deed. She was the subject of This Is Your Life in 2003 when she was surprised by Michael Aspel.
With John Thaw she guest starred in the episode "The Sign of Four" (1987) of the series Sherlock Holmes. She guest starred in episodes of Lewis ("The Point of Vanishing", 2009) and Identity ("Somewhere They Can't Find Me", 2010). A few years later, she appeared in the series Endeavour (the prequel to the Inspector Morse series), in the episode "Rocket" (2013).
Seagrove is an animal rights activist and an advocate for deregulation of the herbal remedy industry in the United Kingdom, and promotes a vegetarian diet.
Her partner since 1994 is the theatrical producer Bill Kenwright, chairman of Everton F.C.. The couple appeared together as contestants on a charity edition of ITV1's Who Wants to Be a Millionaire?, winning £1,000. They also appeared together on a celebrity edition of the BBC's Pointless which aired on 3 January 2014. She resides in Little Venice, London.
Seagrove was previously married to British and Indian actor Madhav Sharma from 1984 to 1988 and then dated film director Michael Winner until 1993.