A pioneer of women's hockey, Heaney is credited with aiding the growth of the sport. Her offensive prowess as a defenceman earned her comparisons to National Hockey League star Bobby Orr, particularly after she flew through the air after scoring the gold medal-winning goal in the inaugural world championship. In 2008, Heaney became one of the first three female inductees, along with Angela James and Cammi Granato, to the International Ice Hockey Federation (IIHF) Hall of Fame. She was the third woman, after James and Granato, to be inducted to the Hockey Hall of Fame, and will be inducted into Canada's Sports Hall of Fame in 2014.
Heaney was born October 1, 1967, in Lurgan, County Armagh, Northern Ireland. Her parents, Mike and Kathleen Heaney, emigrated to Canada when Geraldine was one-year-old, but she retained pride in her Irish birth, often returning to Ulster. Her family settled in North York, Ontario, where she grew up and developed her passion for hockey, often playing goal for her brothers on outdoor rinks. A gifted athlete, Heaney also played Gaelic football, soccer, fastball and in-line hockey.
Heaney first joined a girls hockey team at age 10, playing against girls up to six years older than her. She joined the Toronto Aeros in 1980 at the age of 13. It began a career with the organization in which she played over 1,000 games at the senior level and later the National Women's Hockey League (NWHL). She was a member of six provincial championship winning teams and named the Ontario Women's Hockey Association's top defenceman on three occasions: 1987–88, 1991–92 and 1992–93.
While studying recreation facilities management at Seneca College in Toronto, Heaney was recruited to play volleyball, but immediately switched to hockey upon learning the school operated a women's team. In 1987, she led Seneca to an Ontario Colleges Athletic Association championship and was named to both her league and the provincial championship all-star teams.
Heaney was a member of four national championship teams with the Aeros. The only player to appear in the Esso Women's National Hockey Championship every season between 1987 and 2001, Heaney was named the best defender of the tournament in 1993, 1997 and 2001 and was named most valuable player in 1992. Three months pregnant with her first child, Heaney ended her club career in 2004 by scoring the overtime-winning goal to capture the national championship. In recognition of her 27-year playing career, the Aeros retired her uniform number 91 in 2006.
The first International Ice Hockey Federation (IIHF) sanctioned Women's World Championship was played in 1990, in Ottawa. Heaney was selected for Team Canada, but as she was a landed immigrant, she had to rush the process of gaining citizenship before she could play. Canada and the United States were the class of the tournament and met in the final. Heaney scored the gold medal winning goal in dramatic fashion as she deked around two American defencemen before sliding the puck into the net as she tripped over the goaltender and flew through the air in a fashion reminiscent of Bobby Orr's Stanley Cup winning goal in 1969. The goal, coupled with her skills as an offensive defenceman led to Heaney becoming known as the "Bobby Orr of women's hockey".
The 1990 tournament marked the first of seven consecutive gold medal victories for Heaney, and she was the only player to appear in the first seven World Championships for Canada. She received the Directorate Award as the tournament's best defenceman at the 1992 and 1994 tournaments, and was named a tournament all-star in 1992.
Women's hockey was added as a full-medal sport for the first time at the 1998 Nagano Games, and Heaney was named to the Canadian Olympic team. While Canada had won every World Championship to that point, defeating the United States in the final each time, the Americans had begun to defeat Canada at other tournaments. Heaney scored two goals and added four assists in six games; however Canada lost the final to the United States, 3–1, and settled for the silver medal.
Heaney planned on the 2002 Salt Lake Games being her final tournament. She ended her international career with an Olympic gold medal after Canada defeated the United States 3–2 in the final. The final was controversial as the American referee called 13 of the final 16 penalties in the game against Canada. Heaney described the feeling of the Canadian players following the game: "We got an unbelievable number of penalties. We never had any idea that could happen. [The officials] tried to give them the game, and we weren't going to let that happen." In addition to celebrations in Canada, Heaney was recognized as a sporting hero in Northern Ireland.
Heaney also played in two World Ball Hockey Championships. She won a gold medal in 1992 and silver in 1994.
An offensive defenceman, Heaney appeared in 125 games with the Canadian National Team, scored 27 goals and recorded 66 assists. In World Championship play, she holds Canadian records for most games (35), goals (8), assists (28) and points (36) for a defenceman. A pioneer of modern women's hockey, Heaney has been recognized by numerous institutions. She has been inducted into the Ontario Colleges Athletic Association and Canadian Ball Hockey Halls of Fame.
In 2008, Heaney joined countrywoman Angela James and American Cammi Granato as the first women inducted into the IIHF Hall of Fame. Proud of her induction, Heaney saw it as a sign of worldwide recognition of women's hockey, and added: "There are so many young girls playing hockey now, it's amazing. I really feel we need to promote the game worldwide, not just in Canada, and inducting women now should help that." Five years later, Heaney became the third woman (following James and Granato in 2010) to be inducted into the Hockey Hall of Fame as part of its 2013 class. She will be inducted into Canada's Sports Hall of Fame as part of its 2014 class.
Heaney settled in Ancaster, Ontario, following her playing career where she and her husband John are raising their two children, Shannon and Patrick. Heaney remains active in hockey; she turned to coaching and spent six seasons as coach of the University of Waterloo Warriors women's hockey team, though the program often struggled as it lacked the resources compared to larger university programs. Heaney left Waterloo in 2012 to coach her daughter's novice team.