She started her sports career in her hometown in 1949, and from the mid-1950s she and Sjoukje Dijkstra were successful in a sport which had hardly been known in The Netherlands at all until then. Initially, Haanappel was the most successful, and won the first of four Dutch championships in 1955. Though Dijkstra was the physically more powerful skater, Haanappel was more elegant and had style and limberness. Unfortunately she lost confidence in herself, which could not be solved easily in the absence of sports psychologists, and Dijkstra became the most successful of the two skaters. This did not lead to great rivalry though, as they practically grew up together and have always been friends.
Haanappel thrice won the bronze medal at the European Championships, in 1958, 1959 and 1960. She also took part in two Olympic Games; as a fifteen-year-old she came 13th in 1956 (one place behind Dijkstra), and in 1960 she came 5th. After the EC of the same year she ended her competitive career, and started skating professionally, a.o. for Holiday on Ice.
Since 1975 Haanappel has been working as a television presenter and commentator, first for Studio Sport on a Dutch national channel then for [Eurosport] and currently as a freelancer. She is also a member of the Council of the Royal Netherlands Skating Federation (KNSB) and lives in Belgium.