She was born in Hartfield, Sussex. Her father owned an antiques shop near Kew Gardens and in her late teens she had a temporary job at Biba, the famous boutique located on Kensington High Street, London. It was at the instigation of Barbara Hulanicki, founder of Biba, that she became a model. In the late 1960s and early '70s, she was regularly featured in the work of Disc Cartoonist J Edward Oliver, who on one occasion devoted an entire strip to her entitled 'The Life and Habits of the Madeline Smith'.
She first worked for Hammer Film Productions in Taste the Blood of Dracula (1969), billed as 'Maddy Smith' and playing an East End prostitute. Among her other film appearances, she played opposite Ava Gardner in Tam-Lin, Peter Cushing in The Vampire Lovers and Frankenstein and the Monster from Hell, Diana Dors in The Amazing Mr Blunden, Frankie Howerd in Up Pompeii and Up the Front, and Vincent Price in Theatre of Blood. In 1973 she played the Bond girl Miss Caruso in the post-opening titles sequence of Live and Let Die, the first James Bond film starring Roger Moore. She was recommended for the role by Moore himself, having previously appeared with him in an episode of The Persuaders! on TV.
Her television credits include Doctor at Large (1971), The Two Ronnies (appearing in the serial 'Hampton Wick', 1971), Clochemerle (1972), His and Hers (1970) with Tim Brooke-Taylor, Casanova '73 (1973) with Leslie Phillips, Steptoe and Son (1974), The Howerd Confessions (1976), Why Didn't They Ask Evans? (1980) and The Steam Video Company (1984). She was a member of the regular cast of the BBC2 series The End of the Pier Show (1974) and In The Looking Glass (1978) alongside satirists John Wells and John Fortune and Composer Carl Davis. One of her last film credits, The Passionate Pilgrim (1984), turned out to be the final screen appearance of Eric Morecambe.
Having given birth to a daughter, Emily, she gradually wound down her acting career. Her husband, actor David Buck, died from cancer in 1989. Twenty years later she was interviewed in, and was the cover star of, the coffee-table book Hammer Glamour. She returned to acting in 2011. In 2015 she appeared as a contestant on the red team in the BBC antiques gameshow Bargain Hunt.