Catherine Cox was born in Whangarei, New Zealand but moved with her family to Australia when she was six. Cox started playing netball at age 11, starting at the Hills District Netball Association in New South Wales. By 1992 she had represented New South Wales at under 17 level. She first represented her country at Under 21 level in 1994. She was an Australian Institute of Sport scholarship holder. She was first selected for the Australian national team squad in November 1996 and made her Australian team debut in 1997 against South Africa, aged 21.
Cox's next Australian appearance was in the 1999 Test Series in Australia against England. After a knee operation at the end of 1999, Catherine co-captained the Perth Orioles for the next two seasons. She was selected again in 2000 after the retirement of longstanding shooters Vicki Wilson and Jenny Borlase but did not maintain her place. She rejoined the Australian Netball Diamonds in 2002 and played in integral part in the victory in the Commonwealth Games in Manchester, and has been a fixture in the team since. In 2002, she joined the Sydney Swifts and shared shooting roles with Jane Altschwager, Megan Dehn and Susan Pratley and contributed to the Swifts consecutive grand final appearances from 2003 to 2007, with success in 2004, 2006, and 2007.
Australian Netball Diamonds
Cox appeared for the national team at the 2002 Commonwealth Games and played after half-time in the double over-time final win over New Zealand. She appeared for Australia in the 2003 Netball World Championships, and played the last quarter of the grand final loss by two goals to New Zealand. Cox also played for Australia's successful team at the 2007 World Championships in Auckland. Cox was vice-captain in Australia's successful campaign in the 2011 World Netball Championships in Singapore, after Natalie von Bertouch replaced the injured Sharelle Mcmahon as captain. After von Bertouch was injured, Cox became captain for the series against New Zealand and England in October 2011. During the tournament Cox scored her 2000th goal for Australia and became Australia's fourth most highest capped player, behind Vicki Wilson, Sharelle McMahon and Liz Ellis. On 20 September 2012 during the second test against the New Zealand Silver Ferns in the Constellation Cup series, Cox earned her 100th test cap to become only the fourth player in Australian netball history to reach the century mark.
Cox captained the New South Wales Swifts in the inaugural ANZ Championship season in 2008 and was awarded player of the match in the grand final win against Waikato Bay of Plenty Magic. In June 2010, Cox played her 200th domestic match against the Melbourne Vixens, the second Australian to reach that milestone after Sharelle McMahon. In August 2011, Cox lost the captaincy of the New South Wales Swifts and left to join West Coast Fever. Cox was the captain for the West Coast Fever and is currently the only player to be captain for two different teams since the inaugural season. In 2014 she joined the Melbourne Vixens, which went on to win the ANZ Championship that year. That year in 2014, she retired from the ANZ Championship. Cox was a side-line commentator for Sky Sports for the 2014 Constellation Cup Series in New Zealand, is a commentator for Fox Sports for the ANZ Championship.