Catherine Feller's childhood was spent in Italy, where she resided until the age of eleven, when her parents' separation led her to relocate to England. She enrolled at the Aida Foster Theatre School, where she studied drama, dance, and education. Upon graduation, she embarked on a career as a fashion model in 1954, marking the beginning of her journey in the entertainment industry.
The following year, she made her theatrical debut at the Bristol Hippodrome and the Lyric Theatre in London. Feller then joined the West End-based Tennent Productions Ltd. theatre company until 1955. Her subsequent roles included playing the title character in Gigi at the Windsor Repertory Company in 1957 and later, Catherine in A View from the Bridge at the Sam Wanamaker Playhouse. Additionally, she portrayed Lucy Gilham in Ladies in Retirement at the Ashcroft Theatre in Croydon.
Feller's television career took off in 1954, when she made her screen debut with a small role in The Belles of St. Trinian's. She went on to appear in various anthology drama series, such as The Edgar Wallace Mystery Theatre and the Somerset Maugham Hour, as well as guest-starring in One Step Beyond, Ghost Squad, and The Saint. Her most notable role was as the vintner's daughter who falls in love with Oliver Reed's lycanthrope in Hammer's The Curse of the Werewolf in 1961.
Feller also had a recurring role as Dominique in the ITV miniseries Lillie, which was based on the legendary Victorian stage diva Lily Langtry. Furthermore, she played the wife of communist town mayor Peppone, the main character's rival, in the BBC adaptation of the classic comedy The Little World of Don Camillo in 1981.
Throughout her career, Feller has worked for RAI broadcasting in Italy, where she has also lectured and given courses on oratory, eloquence, and conversational ability. Additionally, she has worked as a translator for Vogue Gioiello, an Italian jewellery magazine. Feller has been married to the baritone Claudio Giombi since 2001 and currently resides in Milan, Italy.
