She was the first actress considered for the role of Captain Kathryn Janeway in Star Trek: Voyager (1995), but French-Canadian actress Geneviève Bujold was cast instead, only to resign after two days of filming because she was not used to the demands of a weekly TV series. The role finally, and permanently, went to seasoned American actress Kate Mulgrew.

They married in 1982, together working on a TV production of A Month in the Country (1985).

Her marriage to actor Marlowe had run its course by 1977, and she met director Bill Hays that same year, who had two children from a previous marriage.

Extremely visible on TV with frequent work in such series as The Persuaders! (1971), The Adventurer (1972) and the cult sci-fi series Space: 1999 (1975) starring Barbara Bain and Martin Landau playing the role of "Maya", an alien, for which she is best known.

She went on to appear in Moon Zero Two (1969), the James Bond feature On Her Majesty's Secret Service (1969), Callan (1974) and The Black Windmill (1974), but is best known at that time for the slapstick comedy The Return of the Pink Panther (1975), which marked Peter Sellers' cinematic revisiting of his "Inspector Clouseau" character.

While filming Amsterdam Affair (1968), she met and married actor William Marlowe, subsequently moving to London.

Her inauspicious debut (sometimes billed as Catherine von Schell) was in the German film Lana, Queen of the Amazons (1964).

In 1957, her father joined Radio Free Europe, taking the family to Munich where she developed an interest for acting and trained at the prestigious Falconberg School.

In 1950, her family emigrated to the States and Baron von Schell Bauschlott renounced his title in order for his family to gain citizenship. Catherine entered a convent school in New York's Staten Island area.

Born in Budapest, Hungary, her true name is Katherina Freiin Schell von Bauschlott, the scion of a once wealthy German patrician family. Her father, the Baron Paul Schell von Bauschlott, was a well-respected diplomat until the Nazis confiscated their estates during WWII, while her mother was Countess Katharina Maria Etelka Georgina Elisabeth Teleki de Szék. Her family was living in poverty until 1948 when they sought asylum in Vienna and Salzburg as the communist regime began to take hold in Hungary.

Had a brother named Peter Freiherr Schell von Bauschlott (1941-68).