Known as "The Bear", Ronaldson played for the Eastside Spectres, South East Melbourne Magic, Victoria Titans, Perth Wildcats and New Zealand Breakers in the NBL.

He also represented Australia at the 1996 Olympic Games in Atlanta and again in 2004 in Athens In 1989, Ronaldson played for the Australian Institute of Sport in the SEABL.

[2][3] Ronaldson made his NBL debut in 1990 with the Eastside Spectres under the coaching of Brian Goorjian, playing two seasons there.

When the Magic also merged with another club in 1998–99, this time with cross-town rivals the North Melbourne Giants, Ronaldson once again signed with the resulting team: the Victoria Titans.

[11] In addition to his NBL career, Ronaldson represented Australia at international level on numerous occasions, making his debut for the Boomers at the 1994 FIBA World Championship in Toronto, Canada.