Fahey is a product of the highly successful Timaru Girls' High School team that dominated the national secondary schoolgirls' competition during the late 1990's. She later became a member of the 2002 NZC Academy.

She debuted for the White Ferns during the 2003 tour of India in spectacular fashion, averaging over 50 with three half-centuries. During the 2005 World Cup in South Africa , she top scored with a memorable 73 not out off 94 balls in the semi-final loss to India.

During the 2005-06 State League competition she scored 360 runs for the State Canterbury Magicians.

Fahey made three half-centuries in the Quadrangular Series in Chennai in early 2007 but failed in the final against Australia where she was dismissed for a duck. She toured Australia in July that year for the Rose Bowl Series but missed out New Zealand's next three series - the tour of England, a series against the same opposition and an ODI series against Australia - after she contracted flu and was diagnosed with chronic fatigue.

In May 2008, Fahey was named in the probables squad for the World Cup 2009.