The Centenary Medal was awarded in 2001 to Australians who had made significant contributions to their community or the nation in the year leading up to the centenary of Federation. While Steve Irwin was a beloved figure known for his conservation work, he was not awarded the Centenary Medal.
It's possible you're thinking of another award or recognition he received. He was known for:
* The Logie Award: He won the Logie Award for Most Popular Personality on several occasions.
* The Australian of the Year: He was nominated for Australian of the Year in 2002 and 2004.
* The Order of Australia: He was posthumously awarded the Companion of the Order of Australia (AC) in 2007 for his services to conservation and tourism.
Perhaps you could provide more context about the award you're interested in, and I might be able to help further.