Her father owned an antiques shop near Kew Gardens, while she had a temporary job working at Biba's boutique, a fashion house in Kensington High Street, London, during the 1960s.

In the late 1960s and early 1970s, Smith was considered by many to be very photogenic. She was also frequently the subject of cartoons by J Edward Oliver, which made constant admiring reference to her disproportionately large bust.

Her television acting credits included The Two Ronnies (appearance in the comic serial "Hampton Wick"), Clochemerle, Doctor at Large (5 episodes), The Steam Video Company, and in 1970 His and Hers with Tim Brooke-Taylor. She was a member of the regular cast for the BBC2 series The End of the Pier Show (1974) and In The Looking Glass (1978), along with John Wells, John Fortune, and Carl Davis.

Though credited as 'Maddy Smith', Madeline Smith first worked for Hammer films in Taste the Blood of Dracula (1969), as an East End prostitute, a non-speaking role. Her Hammer Heroine cult status derives primarily from The Vampire Lovers (1970) and Frankenstein and the Monster from Hell (1974); although she appears partially nude in the former, Ms Smith exuded a natural innocence in her role as the target of Ingrid Pitt's vampiric appetites.

Her notable films include:

Ms Smith made her last film in 1984 when she gave birth to a daughter and stopped accepting work. She has now left show business altogether, although she is beginning to work the celebrity circuit, including an appearance at Manchester's Festival of Fantastic Films in 2004. She has also auctioned on eBay a dinner party with herself as guest host and speaker.[citation needed]