Frank Neuhauser had already outspelled more than two million schoolchildren to become the last speller among nine finalists. His winning word was easy for him, thanks in part to the common garden flower that his family grew in the backyard: “G-L-A-D-I-O-L-U-S.”

With that, the 11-year-old from Louisville, Ky., became the first National Spelling Bee champion. It was June 17, 1925.

Tens of millions of grade-school spellers later, the 100th anniversary of what is now the Scripps National Spelling Bee will close on Thursday night with the crowning of another new champion.

The final word is likely to be a bit more challenging than what Frank faced — words in last year’s final round included “desmotrope,” “heautophany” and “nachschläge” — and the payoff will be significantly larger. Frank went home with $500, about $9,200, with inflation factored in. The winner on Thursday will take home $50,000.

A lot has changed since that first contest. Today’s competition is televised and attracts spellers from around the world. But Thursday night’s competition is about remembering a century of spelling, and dozens of past champions will be there to cheer on the next member of their exclusive club.

“We have 42 of our past champions, which is over half of our living champions, who are coming back this year. We’ve never seen an assemblage of past champions like this,” said Corrie Loeffler, the bee’s executive director. Ms. Loeffler, herself a former national spelling bee competitor, said champions from as far back as 1960 will be attending to help welcome a new peer to the club of former winners.