Marianne Illing studied and played at Carleton University in Ottawa where she was a four-time OUA all-star, female athlete of the year in 2000, and graduating athlete of the year in 2002. She also set a provincial record for most goals in a season for men or women with 69. She started playing water polo in 1990 with her high school team at Glebe Collegiate.
Illing also played with a French pro club for five years. In February 2003, she played with the French club from Nancy in the European Club Championship qualifiers. Their second place finish qualified the team to move on to the semi-finals in Hungary.
