The businessman, philanthropist and New Zealand Sports Hall of Fame patron said he had changed his will this week to include the pledge.
For it to take effect, the facility would have to move from the Dunedin Railway Station to the the Edgar Centre indoor sports venue, in Andersons Bay.
Sir Eion was a driving force in building the centre in the 1990s.
He wanted the hall of fame and museum to be a world-class attraction and said his family would commit $500,000 to an IT upgrade led by computer graphics innovator Sir Ian Taylor.
Sir Eion (76), of Queenstown, was diagnosed with pancreatic cancer late last year.
Sir Ian, whose company Animation Research Ltd is run from Dunedin, said the pledge was an incredible gesture from a remarkable man.
"I’m flattered he has entrusted us with that responsibility and we are not going to let him down, if this goes ahead."
Sports hall of fame chairman Stuart McLauchlan said it had always been the plan for the new hall to have interactive elements and he called the pledge from Sir Eion very generous.
Sir Ian and Mr McLauchlan said other parties would need to pitch in to turn Sir Eion’s vision into reality.
The sports hall of fame has been at the railway station since 1999, but it has operated on a modest budget and the displays there are static.
A consultant concluded last year the status quo was not sustainable and it was not essential for the hall to remain in Dunedin.
Sport and Recreation Minister Grant Robertson said last month there was an opportunity for the wider sports sector and people who believed in the hall of fame to step up.
The Dunedin Indoor Sports Venue Trust, which runs the Edgar Centre, confirmed last week it will study whether it is feasible to expand the building so it can host the hall of fame and more sports.
Trustee Alan McKenzie has said the Edgar Centre would need to expand to accommodate the hall.
The Andersons Bay building is owned by the Dunedin City Council, which helps to fund the hall of fame.
The council also owns the central city railway station and exhibits there include New Zealand’s first official Olympics gold medal, won by boxer Ted Morgan, in 1928.
Sir Eion said the Edgar Centre was the logical place for the hall, as the centre already attracted hundreds of thousands of visits a year from people who were interested in sport.
Sir Ian said technology could enhance story-telling for the hall of fame in many ways.
New Zealand had amazing stories that could be brought to life, Sir Ian said.
Creating a special experience, including interactive elements, should make the venture self-sustaining.
New Zealand’s government has historically contributed $100,000 a year to the national sports hall of fame through Sport New Zealand grants.
By contrast, developing and redeveloping the Australian Sports Museum attracted millions of dollars in government funding, at state and national level.
Sir Ian said Sir Eion’s gift could get serious discussions rolling about what was possible in New Zealand.
"It’s New Zealand’s sports museum, not just Dunedin’s."
