Fiore's father, together with one of her uncles, owned a clock and watch shop in Amsterdam , and was also the founder of the former Clock Museum, once part of the Amsterdam Municipal Museum (Amsterdams Stedelijk Museum). The Clock Museum was later relocated to Utrecht, and today it is incorporated in the Gold, Silver and Clock Museum in Schoonhoven. Faddegon’s father was also editor of the Magazine for Watchmakers (Tijdschrift voor horlogemakers), published by the Faddegon brothers. Faddegon’s family left Amsterdam in 1924 and moved to Bussum. Music was an integral part of family life; every child was taught to play an instrument, and together they held "chamber concerts" for piano, violin, cello, and triangle, the instrument Fiore played.

Faddegon was ten years old when her father died, and soon her family lived with a significantly reduced income. Faddegon was sewing and altering her own clothes instead of purchasing them. In her artistic work, she chose to use inexpensive and lesser quality materials and to draw on both sides of her sketch paper. She also had to forfeit piano lessons. Faddegon’s piano teacher initially taught her for free until Faddegon could no longer afford the cost of transportation to her teacher’s house. Her teacher also discovered that Faddegon’s alto voice could open doors to becoming a professional singer, but lack of money kept her from pursuing a possible career in this direction. That difficult time, together with the economic depression of the 1930s and World War II, left an indelible mark on Faddegon’s life. After finishing secondary school, Faddegon worked as a secretary for the municipality of Bussum, and was given private lessons from artists of the Laren School (a stylistic movement in Dutch art), located in Het Gooi, an area in central Holland. Later, she attended the Art Academy in Amsterdam. During those years, she worked closely with other professionals, who greatly influenced her artistic style; among them were sculptor Johan Polet, gold and coppersmith Pim Polet, violin maker Maree, and other well-known artists of the time.

During this time in her creative life, Faddegon produced many portrait paintings, including those of the Kreymborg family, owners of the Kreymborg clothing store chain, and those of the Daniels family, importers of Junghans clocks. Faddegon had a keen ability to read and then articulate an individual’s personality—and their inner self—through her portrait paintings. Even though she did not have children, she demonstrated a remarkable innate ability to handle children with ease and made them willing subjects to pose for her portraits.

Faddegon also taught drawing at the secondary-school level for several years during the late 1960s. It was during this period that she met her second husband Rudolf Smith. During their 30-year marriage, Faddegon expanded her artistic activities, using different materials and techniques applied to a wide variety of subject matter.