Keach was named in Australia's team for the Aug. 5-21 Olympics alongside Edwina Tops-Alexander this week, his only previous Olympic experience having come at the 1988 Games.
Now 51, Florida resident Keach is hoping to improve upon the fifth place in the team eventing competition and 23rd in the individual event he achieved nearly three decades ago in Seoul.
"I remember the whole Olympic experience and I enjoyed it very much," he said in an Australian Olympic Committee (AOC) news release.
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"I remember going to the opening ceremony and closing ceremony and things like that. We had good horses and riders on our team but in the end things didn't quite go our way.
"Looking back it would have been ideal to have another two years of competition under my belt. I was young and inexperienced for international competition. The end result was disappointing."
Keach, who took a long break from show jumping in the 1990s and 2000s, would claim the Australian record for the longest gap between Olympic appearances in Brazil, the AOC said.
Sailors Karyn Davis-Gojnich and Nicky Bethwaite previously held the record courtesy of the 16-year gap between their participation in Seoul and the 2004 Olympics in Athens.
(Reporting by Nick Mulvenney, editing by Peter Rutherford)
