Lou Gish, who has died of cancer aged 35, was a bright and sassy actor of natural poise and comic edge. The daughter of the actors Roland Curram and Sheila Gish (obituary, March 11 2005), she demonstrated her range in her last two stage roles.
At the tiny Gate Theatre in Notting Hill, west London, in January last year, she played General Pinochet's Spanish lawyer in Thea Sharrock's riveting promenade production of Fermín Cabal's Tejas Verdas (Green Gables), a moving memorial to Chilean torture victims. Last summer she took on the role of Goneril in Steven Pimlott's lucid version of King Lear, starring David Warner, in the Minerva Theatre, Chichester.
In the first, she was sleek, reasonable, assured. In the second, she tore up the stage, dashing to the floor the Bible proffered by a distraught Albany (Raad Rawi) and channelling her evil complots through a serpentine presence beautifully contrasted with Zoe Waites's choleric Regan. Her younger sister, Kay Curram, played Cordelia.
Lou and Kay were returning to Chichester in part to memorialise their mother's last stage performance there - as Arkadina in The Seagull in 2003 (a production in which Kay played Nina) - but also to get over it. Typically, they arranged company visits to the local bowling alley and teased their leading man by calling him "Dave" - "He's so not a Dave," they said. Warner himself described Lou as "a wonderful, positive presence, a superb actress whose spirit remained with us for the entire run". She had been forced to leave the production when her illness took hold again.
Lou Gish was born and raised in London. After Macaulay church school, Alleyn's in Dulwich, and Furzedown school, Wandsworth, she took a degree at Camberwell School of Art. She first thought of going into journalism; as a student she won a prize for an article she wrote for Harper's magazine, and the then editor, Beatrix Miller, said she would take her on after graduation.
But Lou decided to change direction and took an office job with the actors' agent Jeremy Conway, where she answered the telephone and served the tea, sometimes jokingly dressed in a waitress uniform. A role in a fringe production in Paddington led to the acquisition of an agent of her own, and a notable cameo in Sean Mathias's 1994 revival of Noel Coward's Design for Living at the Donmar Warehouse. Rachel Weisz was a sensational, sulky Gilda in this production, and Gish, no way fazed, played Helen Carver as a screeching socialite in a glittering sheath.
When her parents first separated (Sheila Gish later married the actor and director Denis Lawson), Roland Curram sombrely announced to his daughters that he was coming out as gay. No big surprise there, said Lou, "as he had brought us up on a diet of Judy Garland, Bette Davis, Joan Crawford and Barbra Streisand." Gish and Curram had met while working on the film Darling in the mid-1960s. The star and the director, Julie Christie and the late John Schlesinger, were Lou's godparents - the coolest, she said, in the world.
In a second collaboration with Mathias, Lou played a mannish playwright and adoring assistant to Sian Phillips's Marlene Dietrich in Pam Gems's Marlene. She specialised in such strong, but marginalised, romantic figures: at the Watford Palace in 1998, in Phyllis Nagy's skilful adaptation of Patricia Highsmith's The Talented Mr Ripley, she played Marge as a hilarious piggy-in-the-middle. Later that year, she joined her stepfather Denis Lawson's production of Little Malcolm and his Struggle against the Eunuchs, starring Ewan McGregor, at the Hampstead Theatre, and subsequently in the West End. She played Ann, the object of the lads' fear and misogyny - and of a brutal attack - with devastating contempt.
In 1999, Michael Billington described in this newspaper how Lou - slim, green-eyed and dark-haired - lit up the Chichester stage as a rejected fiancée in Maria Aitken's revival of Noel Coward's underrated comedy Easy Virtue. She was the perfect, swish, middle-class Helena in Look Back in Anger at the Bristol Old Vic in 2001, and an effortlessly aristocratic Duchess of Malfi at the Salisbury Playhouse the following year. Of this latter performance, Alastair Macaulay wrote in the Financial Times that "she doesn't invite us in to her tragedy; we are riveted by it from a distance."
Over the last 10 years, Gish appeared regularly on television in such series as EastEnders, Casualty, Doctors, Wire in the Blood, Couplings and Where the Heart Is. She is survived by her partner, the actor Nicholas Rowe, and her father, stepfather and sister.
· Louise Gish, actor, born May 27 1970; died February 20 2006