Borner played 518 NBL games over 22 seasons for four separate teams: Coburg/North Melbourne Giants, Illawarra Hawks, Geelong Supercats and Canberra Cannons. Borner, a 6"10" (208 cm) tall Centre, also competed for the Boomers in four Summer Olympic Games: 1984 in Los Angeles, 1988 in Seoul, 1992 in Barcelona, and 1996 in Atlanta.
He was named as the NBL"s Most Valuable Player for the 1985 season, becoming the first Australian born player to win the award. Borner won his only NBL Championship in 1989 as a member of the North Melbourne Giants who defeated the Canberra Cannons 2-0 in the best of 3 Grand Final series. Borner was inducted into the Australian Basketball Hall of Fame in 2006 and was awarded the Order of Australia medal on Australia Day in 2009.
