In 1966, Cavani made her first dramatic work, a film for RAI on the life of "Francesco D'Assisi" (St. Francis of Assisi). The result played at the Venice Film Festival and won an award at the Valladolid Film Festival. Having achieved a degree of success, she moved into feature filmmaking, co-writing and directing "Galileo" (1968). The film garnered controversy for its extreme anti-Church establishment viewpoint which led to the Vatican's attempt to suppress the film. Nevertheless, Cavani proved her mettle and received the lion's share of acclaim for a balanced depiction of ideas and the persecution of scientists and thinkers by the Inquisition. Her next efforts, "I Cannibali" (1969), starring Britt Ekland, and "L'Ospite/The Guest" (1971) both conveyed her interests in repressive social mechanics and challenges to traditional authority. "Milarepa" (1973) was a richly complex work which raised questions about violence in society while following the dual stories of an 11th Century youth on a spiritual journey in Tibet juxtaposed with a contemporary story of the aftermath of an automobile accident.
Cavani's best known work remains "The Night Porter", in which a former Nazi commandant and the woman he raped in a concentration camp meet again. A box-office success, the film melded the director's themes with graphic sexuality and raised issues about contemporary political views. She further explored these issues in two other films that drew parallels between sado-masochism and the rise of Nazism: "Beyond Good and Evil" (1977) and "Berlin Interior" (1978). As Cavani turned more toward staging operas, her film output dwindled. In 1989, she revisited the life of Francis of Assisi in the feature "Francesco", starring Mickey Rourke. Her last film to date, the 1993 Italian TV-movie "Dove siente? Io sono qui/Where Are You? I'm Here" was about a deaf mute who finds love.